Villarreal1 - 5Barcelona

The Germany international's problem overshadowed an emphatic win for Barcelona at La Ceramica, as he awkwardly landed on his knee right at the end of the first half.

Ter Stegen was in agony as he lay on the ground before being stretchered off, and the early indications were that the 32-year-old had picked up a severe problem that could sideline him for months.

Flick was immediately asked about the German's condition after the game, and he conceded that his goalkeeper's injury was severe, although he refused to put a timeframe on his recovery.

"It doesn't look good for Marc. We have to wait to know the full diagnosis of the injury, but it's true it does appear to be really serious," the former Bayern Munich manager told Spanish TV.

Flick "very sad" about Ter Stegen injury

Flick was then asked in his post-game press conference how he can go about replacing his number one, although he shot down the question and insisted that he was not in a mood to answer it so soon after the incident.

"I don't like this question right after the game. First we have to see what happens with Marc, he's our captain. I'm very sad about what happened. Please understand that I don't want to answer this question. I haven't been able to speak to Ter Stegen," Flick added.

Barcelona will be expected to confirm the diagnosis once more tests have been run, but ESPN report that Ter Stegen's problem might be serious enough to rule him out for the rest of the season.

The 32-year-old's lengthy absence would be a massive blow for Barcelona, whom he has made 420 appearances for since joining from Borussia Monchengladbach in the summer of 2014.

Ter Stegen inherited the captain's armband from the departed Sergi Roberto earlier this year, but his 2023-24 season was also disrupted by a back injury, which saw him miss 19 games for club and country.

Who can replace Ter Stegen in goal for Barcelona?

Following Ter Stegen's enforced withdrawal on Saturday, his designated number two Inaki Pena saw out the game, and the 25-year-old should now be able to look forward to an extended run of games in between the sticks.

Pena came through Barcelona's La Masia network but has only made 22 appearances for the senior side in all tournaments, having been in Ter Stegen's shadow ever since breaking into the first-team ranks.

Flick also has 20-year-old Barca Atletic goalkeeper Ander Astralaga at his disposal, but the 2004-born youngster is yet to make a competitive appearance for the Blaugrana first team.

Ter Stegen's injury was a blot on an otherwise triumphant day for Barcelona, who demolished Villarreal thanks to braces from Robert Lewandowski and Raphinha either side of a Pablo Torre effort.

Flick's side remain top of the table with six wins from their opening six games and are next in action at home to Getafe on Wednesday evening.