After coming back from a six-point deficit, 0-4 to 1-7, at half-time Dublin lost the game in the fifth minute of stoppage time to a Conor Loftus free after Diarmuid O’Connor was brought down by Dublin’s Tom Lahiff.

It came at the end of a game in which Mayo looked on course for their first U21 football final in 10 years until Dublin came back to lead by four points with 12 minutes left thanks to Con O’Callaghan, Colm Basquel and Michael Deegan.

A 40th minute goal from their leading scorer Con O’Callaghan brought Dublin level at 1-8 apiece on their way to the 1-13 to 1-9 lead, but Mayo stirred themselves for a final push.

They got four points, three of them from Liam Irwin frees and the fourth from play by Matthew Ruane, before Basquel and Loftus exchanged points to keep them neck-and-neck in the third minute of stoppage time.

However, the Crossmolina man coolly struck the final free send Mayo to the decider on April 30.

It came after a first half which saw Mayo storm ahead 1-4 to 0-0 in the first 15 minutes of the game, Young Footballer of the Year O’Connor scoring their major in the tenth minute, before Con O’Callaghan registered a free and a score from play.

Along with Glenn O’Reilly's point and Paddy Small's free, Dublin were rallying only for a Loftus free just before the interval handed Mayo a comfortable lead.

There were more points for the Connacht champions from their Captain Stephen Coen and Shairoze Akram, who eventually saw their team progress to the final after five minutes of stoppage time.

Scorers for Mayo: Diarmuid O’Connor 1-1, Liam Irwin (3f) & Conor Loftus (4f) 0-4 each, Fergal Boland 0-2, Shairoze Akram, Matthew Ruane, Stephen Coen & Fionán Duffy 0-1 each.

Scorers for Dublin: Con O’Callaghan 1-5 (0-3f), Colm Basquel & Michael Deegan 0-3 each, Eoin Murchan, Glenn O’Reilly & Paddy Small (f) 0-1 each.

Mayo

1. Mattie Flanagan (Balla), 4. Eoin O’Donoghue (Belmullet), 3. Séamus Cunniffe (Ballaghaderreen), 5. David Kenny (Aghamore), 11. Michael Plunkett (Ballintubber), 6. Michael Hall (Breaffy), 7. Shairoze Akram (Ballaghaderreen), 8. Matthew Ruane (Breaffy), 9. Stephen Coen (Hollymount/Carramore – captain), 10. Fergal Boland (Aghamore), 18. Conor Loftus (Crossmolina), 12. Diarmuid O’Connor (Ballintubber), 13. Liam Irwin (Breaffy), 15. Fionán Duffy (Crossmolina), 14. Brian Reape (Moy Davitts)

Subs: 2. Eddie Doran (Achill) for Cunniffe (half-time), 17. James Carr (Ardagh) for Duffy (42), 22. James Kelly (Belmullet) for Plunkett (51)

Dublin

1. Lorcan Molloy (St Anne’s), 6. Seán McMahon (Raheny), 7. Eoin Smith (Skerries Harps), 3. Shane Clayton (Ballyboden St Enda’s), 5. Cillian Shea (Kilmacud Crokes), 4. Martin Cahilan (Cuala), 11. Brian Howard (Raheny), 12. Killian Deeley (Na Fianna), 8. Andrew Foley (Clontarf - joint captain), 19. Tom Lahiff (St Jude’s), 10. Colm Basquel (Ballyboden St Enda’s), 17. Glenn O’Reilly (Na Fianna), 24. Paddy Small (Ballymun Kickhams), 14. Con O’Callaghan (Cuala), 23. Michael Deegan (Donaghmore Ashbourne)

Subs: 2. Eoin Murchan (Na Fianna - joint captain) for Cahilan (24), 15. Darragh Spillane (Cuala) for Small (37), 22. Kieran Doherty (St Jude’s) for Deeley (46), 20. Aaron Elliot (Ballymun Kickhams) for O’Reilly (56), 18. Declan Monaghan (Clontarf) for Smith (60+2)

Referee: Niall Cullen (Fermanagh).