Shelbourne had that sinking feeling on a night of high drama as champions Shamrock Rovers finished the season unbeaten.
Finn Harps’ pulled off the great escape with victory against Waterford so Shels will face Longford Town in the one-legged promotion-relegation playoff on Sunday at Richmond Park.
And they must do so without skipper and talisman Gary Deegan who walked on a second yellow card for a needless foul on Graham Burke with five minutes to go.
Hoops boss Stephen Bradley was also dismissed at the death after the Rovers bench reacted furiously to a hefty Dan Byrne challenge on Daniel Lafferty in front of them.
But it was small beer in the greater scheme of things as the Hoops became the first side to finish a league season unbeaten since Rovers did it twice in the 1920s.
Shels boss Ian Morris said: "I'm frustrated but we have to put our big boy pants on and win a game to stay in the Premier Division.
"Gary was sent off for persistent fouling and knew he'd be out of the weekend game after the first booking. We just have to dust ourselves down but it's not doom and gloom, we'll be positive."
Shels put it up to Rovers early on and thought they were off to a flyer when Karl Sheppard headed home in a crowded box after eight minutes, but it was ruled out for offside. And they didn’t get another chance like it as the champions were on their ‘invincibles’ mission and turned up the dial thereafter.
Jack Brady’s double-save to deny Aaron Greene and then Aaron McEneff was heroic stuff, but a sign of things to come because Rovers were ahead after 23 minutes.
A Sean Kavanagh clearance found Byrne just inside his own half and, after nutmegging Deegan on the centre circle, he scampered clear.
The Shels skipper stuck with him but was never close enough and Byrne’s low finish from 20-yards was superbly executed.
Four minutes later, word filtered through of Mark Russell’s goal in Donegal and suddenly Shels, not Harps, were in the relegation playoff.
And thereafter, their own night’s work quickly unravelled as they were 2-0 down 12 minutes into the second-half.
They left nothing behind in their pursuit of a goal, but it was clear they would not be able to save themselves and were left relying on a Waterford equaliser in Ballybofey once Greene turned home Kavanagh’s inch perfect cross from close range.
But Ian Morris’ side refused to believe in lost causes and youngster Alex Cetiner breathed fresh life to their cause off the bench.
Former Rovers man Aaron Dobbs almost scored from one of his crosses with the clock ticking down.
But then all hell broke loose, and just how damaging it will be to Shels’ survival mission remains to be seen this weekend after Deegan’s needles and costly sending off.
SHELBOURNE: Brady; M Byrne, Brennan, D Byrne, O'Hanlon; Deegan, Quinn (McManus 47); Sheppard (Dobbs 61), Farrell, Rooney (Cetiner 61); Kilduff.
SHAMROCK ROVERS: Mannus; Grace, O'Brien, Scales; Marshall, McEneff, Watts, Kavanagh (Lafferty 75); Burke (Williams 85), Greene, Byrne (Finn 63)
Referee: R Harvey
