Manchester United produced their best performance of a mediocre season to upset Manchester City 2-1 in the FA Cup final on Saturday and deprive their rivals of the double.

Goals by teenagers Alejandro Garnacho and Kobbie Mainoo put United in the driving seat by halftime at Wembley and they survived a City siege after the break to win the trophy for the 13th time.

Champions City, bidding to become the first club to win the double in successive seasons, were well below their best in the first half and gifted United the lead in the 30th minute when Garnacho tapped home after a defensive mix-up.

United doubled their lead before the break as Mainoo finished calmly after a superb team move.

City woke up in the second half and Erling Haaland hit the crossbar, but they had to wait until the 87th minute for substitute Jeremy Doku to score and set up a tense finale.

United hung on, however, to ensure they will qualify for next season’s Europa League.

This year's FA Cup title is the second trophy of Erik ten Hag's two-year tenure in charge at United, but it comes amid intense speculation over his future, with potential replacements already sounded out by the club.

It is United's 13th FA Cup title, one behind Arsenal's record of 14. The result also secures United a place in the Europa League next season.

Players and staff embraced Ten Hag on the field after the final whistle as he managed to end a troubled campaign on a high with co-owners Joel and Avram Glazer and British billionaire Jim Ratcliffe watching on.

Saturday's clash was a repeat of last year's final, which ended with City being crowned champions, but it was a different script this time.

City dominated possession in the first half, but United had the more threatening attacks and took the lead through Garnacho.

"It's been a tough season with ups and downs. This is the only thing we've had to look forward to," Mainoo said. "We knew we had to come together. The preparation for this game has been amazing. We've shown we can compete and win games."