Cavan 3-13 Down 2-12
Eamonn Coleman has pulled off many tactical master strokes in his many years in the game, but few can equal the audacious gamble he took at Breffni Park.
His Cavan team was on the way out of the Ulster Football Championship, trailing by five points to a rampant Down side and looking a poor second.
Coleman threw half-fit pair Dermot McCabe and Peter Reilly into the action at half-time, and how they repaid his faith.
They produced a devastating three-goal blast to stun a Down side that had led by seven points with 15 minutes to play.
The duo grabbed a goal apiece, and McCabe set up a third for Jason O'Reilly as Cavan scored a sensational replay win, and earned a semi-final crack at Armagh.
A game which threatened to boil over at times produced 12 yellow cards and two reds, with Cavan attacker Larry Reilly and Down defender Adrian Scullion sent off in the second half, both for second bookings, in separate incidents.
Michael Lyng, Larry Reilly and Sean Johnston were troubling the Down defence with their speed in the early stages, and Lyng punished with his accuracy from dead balls.
But the Mourne men, with Gregory McCartan grafting in midfield and Shane Ward and Eoin McCartan drifting deep to collect and create, remained in touch through Dan Gordon and Aidan O'Prey.
The loss of Ward after 20 minutes through injury was a blow, particularly as skipper Liam Doyle had also been ruled out of the Down half forward line, but they made light of the double setback to strike a sensational double blow late in the half.
That was after Lyng and Mark McKeever had opened up a two points Cavan lead, and the Breffni men appeared to be growing in confidence.
But that feel-good factor was shattered in merciless fashion by Coulter, who struck twice for goals in the space of five minutes.
Gregory McCartan's driven free kick from distance was knocked down by Aidan O'Prey into the path of Daniel Hughes, who picked out Coulter with a flick pass, and the finish was low and deadly.
And in the 35th minute, the Down attacker struck again, fielding another monster delivery from McCartan to turn and pick his spot in the same left corner of Eoghain Elliot's net.
Down led by 2-6 to 0-7 at the break, and Cavan were in deep trouble.
Manager Eamonn Coleman responded by making a treble substitution at half-time, introducing McCabe and Peter Reilly to the inside forward line, and Cahal Collins to the defence.
The move wasn't an instant success, indeed Down extended their advantage to seven points with O'Prey's third score, before the tide began to turn.
McCabe's strength and power as target man at full forward was a huge factor, and when he collected Pearse McKenna's long punt to blast to the net in the 57th minute, the Breffni faithful began to believe.
Eight minutes later, it was Reilly, picking up a quickly taken Lyng free kick to fire in a second goal, and Cavan were a point ahead.
Down were reeling, and although Gregory McCartan brought them level with a 50 metre free, the force was with the home side, and O'Reilly drove in the final two nails, first fisting a point, before netting from McCabe's injury-time assist.