PSG has now lost two of their last three Champions League matches.

French striker Olivier Giroud struck a stunning header into the back of the net on Tuesday to secure AC Milan’s first Champions League win of the season, defeating Paris St Germain 2-1 in Group F.

After Milan Skriniar opened the scoring for PSG, Rafael Leao struck an overhead kick to level Milan with the Parisians.

But 37-year-old Giroud proved that age is just a number to critics after claiming the comeback goal.

The crucial moment drove PSG down to second place in their group with six points, one behind leaders Borussia Dortmund, with the Italian team fetching third spot with five points.

Kylian Mbappe admitted PSG “failed in a few things” in his first press conference since June.

“It is a defeat, a second defeat away from home, it is never easy to lose, we are disappointed. We failed in quite a few things, and we will try to respond at home against Newcastle,” the forward told reporters after the match.

“I don’t know, I don’t know (regarding the difficulties away from home). We are disappointed, we tried to put all the ingredients on our side to win, but it didn’t happen like that,” Mbappe added.

PSG have now lost two of their last three Champions League matches. The other defeat was a 4-1 loss at the hands of Newcastle United last month.

Tensions have spiked in Milan with clashes being reported ahead of the game. A PSG supporter suffered severe injuries after being stabbed in overnight clashes between fans in Milan hours before kick off.

Italian police reported that the fan was stabbed twice in the leg when a group of around 50 Milan fans clashed with visiting PSG supporters.

Two police officers were also hurt as they attempted to restore order.

“Football for us is passion, not hate. Sport is supposed to unite, not divide,” the Italian club said in a statement online.

Tuesday’s violence comes after a Newcastle United fan was stabbed on the eve of the team’s Champions League game against Milan in September.