Kerry were two points down after a storming fightback and, over on the sideline, manager Mickey Ned O’Sullivan was visibly urging the player to shoot for goal.
Instead, Keane tried a handpass across goals in an attempt to pick out colleague Cillian Fitzgerald, who was perched on the goal line.
It didn’t seem a bad play in the circumstances but, from virtually nowhere, Dublin full-back David Byrne emerged to flick the O’Neills away.
In doing so, Byrne began an attack that led to a Dublin point. Instead, of trailing by one as seemed highly likely, the Dubs now led by three.
Just minutes later, Dublin had stretched the margin to eight points at full-time. If ever a scoreline failed to tell the true story of a game, it was here.
In hindsight, missing that goal chance — and seeing it turned into a point at the other end — hit Kerry hard and robbed them off all their momentum.
Dublin will offer no apologies. Overall, they deserved to win having held that same eight-point lead early in the second half.
The difficulties late on will worry Dublin manager Dessie Farrell though. His side were caught by a late Tipperary goal in last year’s final and they’ll meet a Meath team in this year’s decider that showed great heart with late goals themselves to overcome Tyrone and Mayo.
Of course, Meath will have all the motivation in the world to succeed too, having been defeated by Dublin in the Leinster final.
Still, this is a strong Dublin team and they are justifiably favourites to make up for 2011 when Tipp picked their pockets.
They possess physically powerful players, like midfield duo Stephen Cunningham and Shane Carthy, and have real style in attackers Cormac Costello and Niall Scully.
Costello is the son of Dublin GAA chief executive John and is poised for back-to-back All-Ireland minor final appearances in both codes.
It is an incredible achievement and he kicked 1-3 yesterday to underline his rising star status.
He got Dublin going with an opening point in the first minute and when Scully and Carthy followed his lead, within minutes, they were three clear.
Dublin looked dynamic in attack and in the fifth minute, Scully was quickest to react to a shot off the post, eventually passing it off to Conor McHugh who netted.
When McHugh converted a free soon after, Dublin led 1-4 to no score.
Kerry had a couple of bursts of scoring in the half, hitting three points in a row at one stage.
But they were largely outplayed by a Dublin side well able to handpass the ball out of defence and boot it in quickly to their two-man full-forward line.
Costello scored a beautiful solo goal in the 25th minute. He probably should have been stopped earlier but showed real pace and power all the same to slalom in along the right end line, cut back onto his left foot and drill the ball low to the net. A 2-6 to 0-5 lead didn’t flatter Dublin at half-time and when Costello booted over another point soon after the restart, they were eight clear.
On a day of storming fightbacks at Croke Park, Kerry at least made a game of it in the last 20 minutes or so. They tightened up in defence for a start and then looked to players like Jack Savage to get them going in attack.
Savage kicked back-to-back frees in a purple patch of Kingdom scoring. The blitz was inspired by a sublime point from the left wing by centre-back Ronan Murphy. And a goal from Fitzgerald lent fuel to their fire. With 54 minutes on the clock, Kerry now trailed by just 1-10 to 2-9. That’s when they broke forward and played Keane into a position where a goal, which would have put them one ahead, seemed a likely outcome.
But Dubs defender Byrne was typically excellent, capping a great game with that vital intervention and his colleagues raised their own game in response, finally closing out the game with a third goal from substitute David Campbell approaching full-time.
Scorers for Dublin: C Costello 1-3 (1f); C McHugh 1-2 (1f); D Campbell 1-0; N Scully & S Carthy (1 45) 0-2 each; M MacDonncha, G Burke & Shane Cunningham 0-1 each.
Scorers for Kerry: C Fitzgerald 1-0; J Savage 0-3 (3f); C Keane & N Sheehy 0-2 each; D Daly, D Foran & R Murphy 0-1 each.
Subs for Dublin: Shane Cunningham for Gaughan 44, D Gormley for Walsh 48, D Campbell for Scully 54, M Deegan for Burke 59.
Subs for Kerry: D Daly for O Conchuir 27, S Moloney for Sheehy 48, G O’Sullivan for Murphy 49, G O’Shea for Foran & E Doyle for Barry 59.
Referee: F Kelly (Longford).