Arsenal captain Laurent Koscielny has been taken off on a stretcher following an injury during the Europa League clash with Atletico Madrid.
The France international, who started Thursday's semi-final second-leg defeat at the Wanda Metropolitano, went down off the ball with no opponent nearby just nine minutes into the game.
Koscielny appeared in serious pain and was clutching his ankle, suggesting an aggravation of his long-term Achilles problem, and was carried off on a stretcher on 11 minutes.
Calum Chambers, an unused substitute in the 1-1 first-leg draw, came on as a replacement for the 32-year-old, who left the field to applause from all four sides of the stadium.
Koscielny, who now appears likely to miss the World Cup in Russia, revealed last summer that he would require daily treatment to manage his Achilles problem for the rest of his career.