Kai Havertz was left covered in blood after suffering a gruesome injury in the closing stages of Arsenal's defeat to Inter Milan in the Champions League. Hakan Calhanoglu scored the only goal of the game from the penalty spot to condemn the Gunners to a narrow defeat.

Arsenal were pushing for a late equaliser at the San Siro when Havertz attempted to win a header in the box. He was involved in a sickening collision with Inter defender Yann Aurel Bisseck, who was equally as committed to clearing the ball away from danger.

Havertz came off much worse than his opposite number, with blood pouring down his face as he sat dazed on the byline. He needed immediate treatment from the Arsenal physio, who ended up with the striker's blood smeared across the front of his jacket.

Mikel Arteta was left with little choice but to replace Havertz given the grisly nature of his head injury. In a bittersweet moment, it was Martin Odegaard who entered the pitch for the first time since September in place of the German forward.

Odegaard, who had been sidelined with an ankle injury for almost two months, was unable to inspire the Gunners to victory in spite of his best efforts. They huffed and puffed in the closing stages but Inter survived the onslaught and held on to claim all three points.

It came after Arsenal fell on the wrong side of a controversial penalty decision on the stroke of half-time. The referee pointed to the spot after the ball deflected off Mehdi Taremi and onto the outstretched arm of Mikel Merino.

Arsenal legend Martin Keown was left furious with the decision to award Inter a penalty, given that Merino had no time to pull his arm away from the ball.

He said on TNT Sports: "Is the arm in an unnatural position? It isn't. I mean, I don't know who determines that. VAR is never going to intervene and then we have this debate again.

"I think it is ruining our game. It certainly ruined Arsenal's half-time team talk. I think they're hard done by there."

Fellow pundit Rio Ferdinand agreed with Keown, adding: "It is unfortunate that the rules are different in different competitions. I think that is the confusing thing, not only for players but for fans and pundits."