It was a dramatic finish to a game that had looked set to end in frustration for PSG, especially after Lionel Messi saw his penalty saved just after the hour mark.
Rocking an Alabama State University jersey, he performs in the end zone at a football game while joined by a marching band, cheerleaders, and dance squads. Weezy adds some school spirit as he delivers his verse in the stands.
Substitute Martinez sealed the win for Inter from the spot five minutes from the end of the game after Simone Inzaghi's men were awarded a penalty for a handball.
Erik ten Hag's side faced a frustrating wait for the breakthrough with Rasmus Hojlund and Alejandro Garnacho missing big chances at each end of the first half before Victor Lindelof grabbed the winner on 59 minutes.
Manchester City kept their title hopes alive by scoring four second-half goals to thump Aston Villa and end a run of three straight Premier League defeats.
Burnley's hopes of forging a route back into the game took a turn for the worse when O'Shea lost possession near the halfway line before committing a professional foul on Dwight McNeil, earning a the defender a straight red card.
Liverpool reached the FA Cup fifth round with an entertaining victory over Norwich in their first game since manager Jurgen Klopp announced he will leave at the end of the season.
Harry Kane scored twice as Tottenham beat Borussia Dortmund to get their Champions League campaign off to a positive start and end their winless run at Wembley.
As in Sunday's FA Cup semi-final against Coventry, it was a favourable outcome in the end for under-pressure manager Erik ten Hag. But there are some staggering statistics to go with their recent results.
An entertaining encounter looked set to end in stalemate before - with the game entering stoppage time - Firmino soared to flash a header high past Spurs keeper Hugo Lloris from Andrew Robertson's corner.
England captain Harry Kane, inevitably, was involved with a deft touch to release Kingsley Coman, who easily beat exposed United keeper Andre Onana in front of the Stretford End.