Kai Havertz was left with blood pouring from his head after a nasty collision against Inter Milan.
The Arsenal forward was forced off during the closing stages in Italy on Wednesday night.
Havertz required treatment from the Gunners medical staff after colliding with Inter’s Yann Bisseck.
Both players stayed down in agony after the incident before the physios rushed onto the pitch.
Blood could be seen pouring from Havertz’s head whilst he was seen to before making way.
The extent of the bleeding could be seen on the jacket of the Arsenal physio, who was left with a red patch on his coat.
After several minutes, Havertz was helped off and subsequently replaced by Martin Odegaard.
The Gunners captain came on for his first action since August following an injury lay-off.
Meanwhile, Bisseck was able to continue for Inter as they closed out the final moments to secure a 1-0 victory.
Hakan Calhanoglu’s first-half penalty proved to be the difference at the San Siro.
The spot-kick was awarded due to a handball by Mikel Merino just minutes before half time.
However, the decision was criticised by former Arsenal defender Martin Keown, while Ally McCoist demanded a change to the handball rules.
The TNT Sports pundit raged: “Is his arm in an unnatural position.
“I don’t know who determines that… it’s ruining our game, it certainly ruins Arteta’s team talk.”
Wednesday’s defeat is Arsenal’s first in this season’s Champions League and leaves them 12th in the league phase table.
Mikel Arteta’s side are just two points off the top eight, though, with four matches remaining.
