Motherwell all but clinched third spot in the SPL with a deserved victory over Aberdeen at Fir Park.
The hosts took the lead after 61 minutes when Darren Smith stabbed the ball home from close range.
But Motherwell's lead lasted only six minutes as Sone Aluko volleyed a superb equaliser past goalkeeper Graeme Smith.
Both sides attacked in a pulsating second-half and Chris Porter swept home the winner in 80 minutes after a quick counter-attack to floor the Dons.
Well and Dons were looking for victory to boost their hopes of securing third place and a Uefa Cup spot for next season.
Motherwell started the game in third place, three points ahead of the Dons with a game in hand.
After Dundee United's defeat by Rangers, the home side knew victory coupled with a Celtic win over Hibernian on Sunday would put them in the Uefa Cup for the first time in 13 years.
Motherwell went close to breaking the deadlock after 12 minutes following good link-up play between David Clarkson and Porter.
Clarkson headed on Mark Reynolds' pass and confidently controlled Porter's instant return, but the striker volleyed over from 12 yards.Aberdeen had to shuffle their defence when centre-back Andrew Considine limped off to be replaced by Dave Bus.
Walker looked the most threatening player for the Dons in the first-half and Smith had to look lively to save his flashing drive.
Smith gave Motherwell a deserved lead in the 61st minute when he stabbed the ball home from close range for his fourth goal of the season.
Porter headed down a dangerous cross by Hughes and the teenager poked the ball into the bottom corner at the second attempt.
But the Dons restored parity six minutes later when substitute Aluko volleyed home Darren Mackie's cross.
Aberdeen looked far more dangerous after carving out an equaliser, with Barry Nicholson's shot adjudged not to have crossed the line and Aluko going close for the Dons.
Porter put Well back in front when the frontman finished a superb counter-attack to sweep Stephen Hughes' cross past the stranded Jamie Langfield.
Motherwell: Graeme Smith, Brian McLean, Craigan, Reynolds, Hammell, Hughes, McGarry (McCormack 66), Malcolm, Fitzpatrick (Darren Smith 46), Porter, Clarkson, McCormack (Lappin 85). Subs Not Used: Daniels, Lasley, Murphy, Meechan.
Booked: Lappin.
Goals: Darren Smith 61, Porter 81.
Aberdeen: Langfield, Maybury, Touzani, Considine (Bus 17), Foster, Duff, Nicholson, Walker (Aluko 64), Severin, Mackie (Maguire 81), Miller. Subs Not Used: Soutar, Lovell, De Visscher, Ross.
Booked: Touzani.
Goals: Aluko 67.
Att: 8,574
Ref: C Thomson
BBC Sport Player Rater man of the match: Motherwell's Chris Porter 7.57 (on 90 minutes).
Please note that you can still give the players marks out of 10 on BBC Sport's Player Rater after the match has finished.
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