Costello’s 59th minute score put Dessie Farrell’s men in front for the first time in the game but their timing was spot on, as they sealed a final date with Roscommon.

The Leinster champions struggled throughout to break Cavan down, particularly as they were in trouble at midfield. Being unable to field Shane Carthy, who was man of the match in their provincial decider, was a blow but eight first-half wides also proved a major handicap.

They had four of those wides after seven minutes and Cavan hit the front as Tom Hayes used his feet nimbly to create some space from which he executed an accurate finish.

Within seconds, Ciarán Brady had a brilliant point chance but his shot was deflected over by David Byrne.

Although Conor McHugh got Dublin off the mark, the Blues were very wayward with their shooting.

McHugh did land a second to reduce the margin to three but some quick delivery to their inside forwards paid off for Cavan and Joe Dillon was amongst the beneficiaries as they went four points clear.

One of those scores came as a result of a fine pass from the high-fielding Liam Buchanan, after Peter Graham had blocked an effort from the anonymous Peter Mannion at the other end of the field.

It was notable though that Dublin finished with two points from Niall Scully and Cormac Costello to keep themselves in touch at the interval on 0-7 to 0-5, and they might even have led, but for a splendid save by James Farrelly from Costello.

That was the first and only time that Dublin managed to open a congested Cavan defence, and they must have been worried as Peter Reilly’s charges had an excellent point from Hayes, followed by an Enda Flanagan free to lead once more by four points just three minutes into the second half.

Cavan only managed one more point in the remaining 27 minutes and that wasn’t enough to hold off the committed Dubs.

Emmet Ó Conghaile lofted a monster point for Dessie Farrell’s men and Mannion capitalised on some tremendous work by Jack McCaffrey to chip over. Gavin Ivory found the target from the next attack and the margin was down to one.

Hayes was a constant nuisance for the Dublin defence though and he set up Kevin Bouchier for a well-taken score that made it 10-8 with 10 remaining.

The Dubs needed inspiration and it came from senior panellist Costello, who drove in from the right flank before finishing excellently off his left with seven minutes remaining.

McHugh levelled and it was left to Costello to do the honours from a free awarded under the advantage rule, after Gavin Ivory’s shot had hit the post.

SCORERS FOR DUBLIN: C Costello 0-4(2fs); C McHugh 0-3; N Scully, P Mannion, G Ivory, E Ó Conghaile 0-1 each

SCORERS FOR CAVAN: J Dillon 0-3; T Hayes, E Flanagan (fs) 0-2 each; C Brady, M Argue, K Bouchier 0-1 each

DUBLIN: L Molloy, R McGowan, D Byrne, R McDaid, S Boland, J Small, J McCaffrey, P O’Higgins, B Fenton, N Scully, E Lowndes, C Costello, C McHugh, P Mannion, N Walsh. Subs: E Ó Conghaile for O’Higgins (26), G Burke for Walsh (39), G Ivory for Boland (39), S Cunningham for Scully (56)

CAVAN: J Farrelly, B Fortune, K Clarke, P Faulkner, G Smith, C Moynagh, C Brady, L Buchanan, P Graham, M Argue, E Flanagan, A Watson, D McVeely, T Hayes, J Dillon. Sub: A O’Hora for Moynagh inj (23), K Bouchier for Dillon (46), Moynagh for Fortune (49), E Hession for Graham (55), G McGovern for Buchanan (60+1)

REFEREE: D O’Mahoney (Tipperary)