Mayo 1-11 Roscommon 1-10
Mayo produced a late surge to snatch the Connacht U-21 football title in dramatic fashion in wet conditions at Markievicz Park in Sligo.
Roscommon, bidding for their third provincial title in a row, seemed poised for victory when they raced six points clear after just eight minutes.
But while Mayo trailed by five points at the break, they never lost sight of the champions and struck in the dying moments to snatch their 24th title.
Liam Irwin produced the key score for Mayo when he struck a late goal three minutes from time. Mayo had not led prior to that before Irwin fisted home a goal after a cross from James Carr.
Man of the match Diarmuid Murtagh hit back and levelled for Roscommon as the game slipped into stoppage time.
But Mayo finished strongly and Michael Plunkett struck the winner in the second minute of stoppage time after a good passing movement.
Roscommon looked to be on their way when Murtagh shot to the net in the third minute as the champions raced into a 1-3 to 0-0 lead after just eight minutes.
Roscommon led by 1-6 to 0-4 at the interval but Mayo cut the gap after the restart and kept within distance to mount a late winning rally.
Mayo: M Flanagan; D Kenny, S Cunniffe, E Doran; M Hall, S Coen, S Akram; D O'Connor, M Ruane; M Plunkett (0-1), C Loftus (0-3, 0-3 frees), F Boland (0-1); L Irwin (1-3, 0-2 frees, 0-1 '45), B Reape (0-1), F Duffy (0-2).
Subs: E O’Donoghue for Doran (18 mins), J Carr for Loftus (45 mins).
Roscommon: R Fahy; J Connaughton, S Mullolly, K Beirne; F Lennon, U Harney (0-1), B Stack (0-1); T O'Rourke, C Compton; K Farrell, H Walsh (0-1), B Kelly; D Murtagh (1-4, 0-2 frees), H Darcy, R Daly (0-3).
Subs: M Daly for Mullolly (30 mins), R Raftery for Compton (36 mins), C Callinan for Kelly (46 mins), K Smith for Walsh (58 mins).
Referee: J Molloy (Galway).