As Paris Saint-Germain head to Spain to face Villarreal on Tuesday, the French club's quest to win a third consecutive Champions League title is under threat as injuries to key players raise doubts about the strength of their squad for another tilt at European glory. Catch all the action live on SuperSport.

PSG's thrilling 4-2 win two weeks ago against Barcelona was overshadowed by the sight of Khvicha Kvaratskhelia having to be helped off injured in the second half.

The Georgian was probably the best player in last season's Champions League knockout rounds, with seven goals and four assists in eight games up to and including the final against Arsenal.

But the rupture to the anterior cruciate ligament in his right knee which the 25-year-old suffered in the win over Barcelona means he is unlikely to return this season.

That is a hammer blow for PSG, who have become Europe's outstanding club side since Kvaratskhelia joined from Napoli in January last year.

Luis Enrique's team began this season's league phase with three wins from three and are well set to reach the knockout stage, but PSG must now be mulling whether to sign a replacement for Kvaratskhelia in the January transfer window.

"Not especially. No injury means we need to sign a new player. None," Luis Enrique said when asked if PSG now needed to go shopping.

"I already said at the start of the season that our team could stay the same, even with two or three injuries. That said, we are always open to the possibility of new players. But not just because we have injuries."

BARCOLA MISSED? 

PSG had already taken something of a risk by selling Bradley Barcola to Liverpool in August in a blockbuster 145 million-euro ($162m) transfer.

Goncalo Ramos, Lee Kang-in and Ibrahim Mbaye all made significant attacking contributions in the last two seasons, but were allowed to leave too.

However, Luis Enrique described the business done by the club during the summer as "exceptional", saying: "I am very happy to begin the season with the number of players that we have".

PSG signed Maghnes Akliouche, a French international winger or midfielder, from Monaco and Spain's World Cup final match-winner Ferran Torres from Barcelona, each for a reported 50 million euros.

They also recruited Belgian international winger Mika Godts from Ajax for a reported 55 million euros.

Torres scored seven goals in his first six appearances, but has gone six games without finding the net. Godts got off to a slow start but has just scored in back-to-back games.

But as the new signings settle, there are renewed doubts about Ousmane Dembele's ability to stay fit after he suffered a hamstring injury against Barcelona – a player whose minutes were very carefully managed last season is now out for several weeks.

And it is not just in attack where PSG have injuries, with centre-back and captain Marquinhos and left-back Nuno Mendes sidelined.

In that case, perhaps the answer to all their problems is right-back Achraf Hakimi, scorer of a hat-trick in Friday's 5-1 win at Le Havre in Ligue 1.

"He is more of an attacker," said Luis Enrique, who has overseen more wins than any other coach in PSG's history.

"He plays higher up the pitch and has the ability to make runs and set up goals.

"He is the best right-back in the world. What I like is that he is always at the highest level, always ready. That means a lot."

PSG made it nine straight wins in that game, despite having only two starters from last season's Champions League final in their line-up.

With competition to PSG lacking in France, being able to rest key players in Ligue 1 and still win remains something which could help them when it comes to Europe.

"We are going to need everyone if we are going to win trophies, and with the injuries there will be opportunities," insisted Luis Enrique.

The problem is there are few players anywhere who could adequately replace a talent like Kvaratskhelia.