Andoni Iraola caused a bit of a stir with his starting line-up for Liverpool's Champions League game against Villarreal on Tuesday evening

One by one, they were entered into the fray by Andoni Iraola as if to demoralise a Villarreal side already reeling from Liverpool’s whirlwind first-half fightback.

First came Florian Wirtz, introduced at half-time for goalscorer Ronald Araujo as part of a tactical tweak. Then there was Alexander Isak, providing fresh legs down the centre of the attack in place of the effervescent Lewis Koumas.

And finally Bradley Barcola was introduced with the rapturous applause for the departing Rio Ngumoha ringing in his ears.

All three cost Liverpool in excess of £100million. And at a combined outlay of £364m, there has never before been a more expensive trio of substitutions in the history of the game.

But that the triumvirate were benched for the Reds’ latest Champions League clash says much about not only the sudden strength in attacking depth at Iraola's disposal, but also how the Basque isn’t bothered about reputation or price tag as he develops his approach to rotation.

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The Liverpool boss readily admitted during the opening weeks of the season that he was unsure how best to cope with the relentless churn of matches given it was a new experience in his managerial career.

After all, the norm for Iraola at Bournemouth in particular had been time to rest and recuperate players during midweeks in between matches so he could wring every last drop out of his preferred high-octane approach.

It was a similar poser for predecessor Arne Slot, who preferred consistency of selection over heavy rotation. That method served Liverpool well at the start of his tenure, but the Reds were running out of steam towards the end of their title-winning campaign under the Dutchman. And the less said about last season the better.

Part of that was down to the nagging suspicion Slot didn't quite trust a number of his fringe players, and that the latest batch of youngsters - such as Ngumoha and Trey Nyoni - weren't quite ready for continued first-team exposure.

Slot was at least correct on the latter score, with Iraola the beneficiary of that lengthy bedding-in process for the teenage duo. Both impressed on their second successive Champions League starts on Tuesday.

But the Basque is certainly more willing, even if partly through necessity due to Liverpool's injury issues, to give minutes to almost the full range of his squad and, by definition, give a rest to some of his big-name players.

Indeed, Iraola has made at least three changes in each of Liverpool's last seven games, the first time that has happened since the Jurgen Klopp era.

True, his selection against Villarreal wasn't quite as seismic as the infamous trip to the Bernabeu in November 2014 when then Liverpool boss Brendan Rodgers, under pressure after a poor start to the season, opted to rest both Steven Gerrard and Raheem Sterling, no doubt contributing to both departing at the end of the campaign.

And in isolation each decision from Iraola appeared justified. Going into Tuesday's match, Virgil van Dijk and Jeremy Jacquet were the only two outfield players with more minutes than Wirtz this season, while Barcola had started the previous three games and Isak only returned from injury at the weekend.

The real intrigue came with the fact few batted an eyelid at Iraola turning to another triumvirate to bring the firepower. Lewis Koumas, the 21-year-old Wales international, has shot up the pecking order and made a third start in four games down the middle, while on the left Cody Gakpo had been the star performer of the opening weeks and was making his first appearance since a brief spell out injured.

Then, of course, came Ngumoha, whose two assists playing on the right lit up Anfield and cemented his place as a regular first-team option. All this while Victor Munoz, scorer of the equaliser at Brentford, was unavailable.

Having rightly fretted about the lack of attacking options for much of the summer, Liverpool fans are now spoilt for choice. But don't be surprised if Isak, Wirtz and Barcola are back in the starting line-up for the Premier League visit of Brighton on Sunday afternoon.