TACTICAL ANALYSIS: Rafa Benitez was the first to spot Iraola's tweak that helped Liverpool escape a shaky start to win 4-3 against Villarreal

Liverpool's 4-3 league phase win over Villarreal in the Champions League will go down as the night one player broke new ground, but the Yellow Submarine posed a challenge that gave us plenty to learn about how Andoni Iraola's Reds are evolving.

Rio Ngumoha was rightly awarded the Player of the Match award for his outstanding performance, a world class display of wing play that has made Liverpool's well-publicised (and unsuccessful) summer pursuit of Yan Diomande appear bizarre in hindsight.

It was a coming of age performance for the 18-year-old, who became the youngest player ever to assist for Liverpool (twice) in the Champions League, but moreover it was a team performance that showed both how Iraola's system can work brilliantly yet also fail spectacularly.

In hindsight, it was a game that turned on a tactical tweak Iraola made after Villarreal's second goal - a switcheroo that Champions League-winning Liverpool manager Rafa Benitez directly brought up with Iraola about after the final whistle.

Speaking on Amazon Prime's post-match coverage, Benitez praised Iraola for subtly shifting Alexis Mac Allister to a deeper role, effectively swapping the Argentinian midfielder with his junior colleague, Trey Nyoni.

"It's true that after 2-0, we decided to throw Trey a little bit more one-sided to help a little bit on the left in the build-up, put Alexis more on the base and also defensively, [it was] a better adjustment there in the middle," Iraola told Benitez.

"And from there I think we finished really well the first half - just five [or] ten minutes - and we started the same way the second half. But until we hadn't changed those adjustments I think we were really struggling because they were overloading us in the middle and Ronald [Araujo] was not really feeling confident to go all the way [into midfield] and it has cost us, yes."

It was not only his half-time substitution of Araujo for Florian Wirtz (shifting Ryan Gravenberch to right-back) that helped Liverpool go on to win the match, then, but also the change Iraola made to his midfield before the break that ultimately got the Reds back in the game and on track for all three points.

It is rare to see a manager change the game so significantly without a half-time team talk, but it proved effective as Liverpool equalised through headers from Mac Allister and Araujo before going on to wrap up the win through another strike from the No. 10 and a final flourish from Florian Wirtz.

Why were these changes so effective - and could we see more of it as Liverpool increasingly come up against sides who look to disrupt their man-for-man pressing structure?

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Van Dijk just one factor in shaky start

Virgil van Dijk's shocking mistake in heading the ball to Georges Mikautadze to gift Villarreal the opening goal inside four minutes may have left the captain apologising to his teammates after the game, but there was plenty wrong with Liverpool's defending across the pitch in the opening half an hour.

It might well be no coincidence that it was Villarreal who posed the sternest test Liverpool's defence have faced from the start of a game for arguably the entire season.

Inigo Perez, Villarreal's manager worked as Iraola's assistant at Rayo Vallecano, where the former Athletic Club defender made his name as a manager in Spain.

Iraola considered Perez's contributions to Rayo's rise so important that he admitted he "complained" when Perez was denied a work permit to join him at Bournemouth - so there are few coaches better placed to understand his Liverpool system, warts and all.

It was a fellow coach reared in LaLiga that posed the most comparable questions to Iraola's new side previously this season in Alvaro Arbeloa, while Diego Simeone also interrogated Liverpool's man-to-man pressing with the roaming runs of Marcos Llorente when Atletico Madrid visited Anfield.

Arbeloa instructed left winger Alex Iwobi to drop inside to overload the midfield when his Fulham side ground out a 0-0 draw against Liverpool just three days after Atletico lost 2-1 to the Reds in September, Araujo again uncomfortable with tracking his man into more nosebleed-inducing areas.

Perez followed suit here. By instructing Villarreal's left winger, Alberto Moleiro, to drop into midfield in possession - knowing Araujo wouldn't track him all the way - Perez earned his side a key advantage.

With Gravenberch playing a more advanced role, Villarreal essentially were able to generate three against two scenarios in midfield every time they broke the first line of Liverpool's press.

The Dutchman struggled in the No.10 role, looking unsure of where to position himself to counter-press when the ball was lost - as was seen for the second goal when Lewis Koumas and Kostas Tsimikas put themselves in position to compete for the ball when Cody Gakpo lost out in an aerial duel, but were forced to retreat with none of Liverpool's midfielders applying pressure to Pape Gueye on the ball.

Time after time, that put Nyoni and Mac Allister in a difficult position. Outnumbered up until the second goal, Liverpool lost possession in midfield 23 times compared to just 15 for the visitors (Opta).

The Reds were punished last season as Arne Slot's more conservative press failed to limit opposition sides' passing options in build-up; with Liverpool playing a more zonal defensive game, teams were more easily able to generate space in behind the line of the first press to create fast transitional attacks that exposed the limitations of Liverpool's midfielders when running back towards their own goal.

That was the case here again, but not due to a conservative defensive line. Indeed, Liverpool's man-for-man pressing was extremely aggressive against Villarreal, both centre-backs pressing up well into the away side's half - but because Araujo's reluctance to commit left him stranded between defending the right-back 'zone' and preventing his man from being able to turn and carry the ball, that pressing structure sprung a leak.

Therein lies the problem. When sides play man-for-man right across the pitch as Iraola's sides have, they effectively surrender their option to play offside with a typical, flat defensive line.

If their opposition can find a gap in that structure, there is always going to be a lot more space to break into than when facing a compact, more traditionally-organised defence.

And when there is a gap, uncertainty spreads to other players' decision-making, van Dijk being especially guilty of this in an uncharacteristically poor performance. Villarreal were able to generate six shots inside the box in the opening half-hour (Opta) from exploiting this weakness time and again - and frankly, Liverpool were lucky it didn't get worse.

Who needs hydration breaks?

The World Cup drew scrutiny for its introduction of mandatory hydration breaks mid-half, many arguing this effectively split the game into four quarters, allowing managers to make tweaks to address tactical issues that would normally only be possible within the luxury of a full half-time team talk.

On Tuesday night (Oct 20), Iraola proved that astute managers can do this just fine in the space of time it takes to reset after a goal conceded. By essentially switching Mac Allister and Nyoni, he simplified Araujo's role but also played to the pair's strengths more effectively in this situation.

Alexis Mac Allister may have had an excellent season so far, but he has played the majority of his best football as the deepest of Liverpool's midfielders.

This has suited Mac Allister because - there is no nice way of putting this - he has never been the quickest across the ground. The Argentinan's top speed in the Premier League this season is 31.3km/h, putting him in the bottom 50% of midfielders in the division, and playing him deeper means he is forced to chase opponents back towards his own goal less often.

This has never prevented Mac Allister from being competitive - he won two aerial duels against Villarreal, showcasing his ability to negate his own height disadvantage, along with making two interceptions - but he looks better defensively when defending forwards in a whole team pressing structure, using his anticipation to nick the ball ahead of his opponent knowing there isn't a gaping chasm behind him.

With the numbers disadvantage Liverpool faced in the opening half an hour here, Mac Allister was fighting a losing battle from the off; with Nyoni doing more of the running alongside him afterwards, the No. 10 was able to stamp his influence on the game.

For Araujo, things didn't completely improve - the Uruguayan hardly a natural at stepping into midfield - but the switch did simplify his game by reducing the need for him to contribute in attacking areas.

With Nyoni occupying a deeper position reminiscent of an inverted left-back in possession, Tsimikas could provide the width further forward - meaning Araujo would slot in alongside Jacquet and van Dijk in a base of three in build-up.

We've seen variations on this over the last few games as Iraola looks to create overloads in the final third, but here it put Araujo closer to the centre of the pitch where he would find it easier to track Moleiro's movements.

That tweak, which worked even more effectively when Gravenberch replaced Araujo in a hybrid right-back/midfield role at the break, completely wiped out the advantage Moleiro gave Villarreal.

Wirtz sinks the Yellow Submarine

From their second goal up until Moleiro was hauled off after 54 minutes, the away side lost possession in their own defensive third 18 times compared to just twice for Liverpool, making just two entries into the final third and being forced into 13 clearances (Opta).

Simply put, the Yellow Submarine was no longer able to navigate its way out of Liverpool's press, and when Wirtz was introduced for Araujo at half-time, Iraola forced Perez back into reacting to his own tactics.

The complete swing in momentum that occurred after Liverpool went 2-0 down was completed with the half-time substitution, which Iraola told the media after the match gave Liverpool "control".

Wirtz was outstanding in the second half, obviously scoring what went down as the winning goal but also creating two chances, completing two of three dribbles, and winning an extremely encouraging seven of his eight ground duels.

With a 90% passing completion rate, the No. 7 kept things ticking in attack but played with confidence, too, producing several moments of magic to create space for his teammates and altogether looking much more like the player Liverpool thought they were signing last year.

After three consecutive improved performances, in which the German has looked better game by game, supporters will hope we are seeing the beginnings of a redemption arc that Wirtz is far from alone in embarking on this season.

Mac Allister, who scored with a sensational header to get Liverpool on the board in the first half, was rampant in the second. Once again getting into advanced positions after Perez surrendered the initiative by introducing Juan Foyth to put an extra man on Wirtz - as Benitez also pointed out to Iraola - Mac Allister was a dynamo in midfield, clocking more shots (five) and more passes into the final third (14) than any other player on the pitch.

But for Rio's headline-grabbing performance, Mac Allister would have been a shoo-in for Player of the Match, once again reminding onlookers of his class after a dreadful individual campaign in Slot's final season.

Another player, returning from injury in this game, deserves endless credit for improved showings this season. Only Rio won more duels (10/13) than Cody Gakpo (9/13), the Dutchman completing five of his six dribbles and creating three chances.

Though he wasn't quite at the peak levels he showed before the international break, the knock he picked up on duty with the Netherlands appears to have had little impact on his confidence, which was on full display with an attempted bicycle kick in the second half that would have put the cherry on the cake of a scintillating attacking performance.

With Bradley Barcola having scored a hat trick in the previous midweek game against LASK and Victor Munoz Villanueva - should he recover in time - having scored a brilliant equaliser against Brentford at the weekend, the renewed competition for places on the wings has given Iraola a very nice problem to solve.

Rio's 74th-minute withdrawal, though, might have been a hint as to the Basque's selection against Brighton this weekend. With the No. 73 posting double the number of touches in the opposition box (12) as the next closest player after accumulating a mind-boggling nine out of 10 successful dribbles, there is no overstating how impressive a performance this was for the 18-year-old.

After bagging two assists to back up his thrilling play on the ball, the question needs to be asked - if Rio continues adding end product to his game, as well as tormenting defenders from either wing, just how good can this lad become?

That, and the other question: Yan Diomande who?

Is Gravenberch a right-back solution?

While it's unlikely we'll see it against Brighton, Gravenberch's tactical flexibility proved integral to Liverpool's win on Tuesday night and, though he may not have been the standout performer, his display in a hybrid defence/midfield role in the second half will have given Iraola food for thought.

There will be more games where this could be a viable solution for helping Liverpool control games on and off the ball, with Gravenberch having gained enough experience stepping into defence under Slot to look reasonably comfortable drifting between right-back and central midfield areas.

Ironically, given Liverpool's well-documented right-back woes, it is on the opposite flank that the Reds are more likely to be tested by a winger dropping deep against their next opponents.

Diego Gomez, who scored one of the best halfway-line goals you'll see in Brighton's 5-0 thumping of rivals Crystal Palace last week, likes to drift inside into the midfield - meaning Iraola will have to think about how he instructs his left-back to defend against the in-form Paraguayan.

On the whole, the Villarreal game will have been informative to Iraola both for setting up against a team that are adept at beating the first line of an opposition press - like Brighton - and for teams that will look to drag Liverpool's right-back into uncomfortable positions, as is increasingly becoming vogue in the Premier League, not just for teams playing against the Reds but in general.

As the league's tactical landscape continues to shift away from the positional rigidity of Pep Guardiola's possession-based football and more towards a game defined by duels, overloads and man-marking, the three players who have made the highest total number of sprints so far are all left backs: Bournemouth's Adrien Truffert, Ipswich's Leif Davis, and Liverpool's own Milos Kerkez.

Marcus Tavernier and Daizen Maeda also dropped into midfield from the left wing at times when Liverpool faced Bournemouth and Ipswich respectively, demonstrating how Liverpool's opponents continue to try to put their right back in uncomfortable positions - regardless of who's playing there - as the jury remains out on the long-term solution as it has since Trent Alexander-Arnold left last summer.

Ryan Gravenberch probably isn't it, but he certainly could provide another option in games that suit his skillset better than that of Araujo - though the Uruguayan has been excellent in the majority of his appearances to date.

Slowly but surely, solutions are becoming clearer for Liverpool's problems, and the inevitable creases in adapting to Iraola's new system are gradually being ironed out.

With a manager capable of doing so mid-game, as Iraola proved again that he is capable of against Villarreal, there is plenty of reason to be optimistic the the Reds are on the up.