Match ends, Kilmarnock 3, Dundee United 2.
Kilmarnock put an end to Dundee United's unbeaten start to 2015 with a stoppage-time winner from Sam Clingan.
Nadir Ciftci rolled in an early penalty before Josh Magennis drew the Rugby Park side level.
Henri Anier soon restored the lead with his first goal for United, but the hosts dominated the second half and deservedly equalised.
Chris Johnston scrambled in to level and Clingan's late free-kick secured a first win for manager Gary Locke.
The Ayrshire men had only won once at home since Dundee United last visited on league duty back in November, but got their reward after twice refusing to wilt after conceding.
And victory keeps their top-six dreams alive but Jackie McNamara's men fall further away from the Europa League spots.
Before kick-off Kilmarnock announced the signing of striker Nathan Eccleston after his recent release from Partick Thistle, but he had to settle for a place on the bench.
New Dundee United signing Robbie Muirhead, a transfer deadline day signing from the Rugby Park side, also began the match as a substitute.
The Tangerines were given the chance to take an early lead when Manuel Pascali bundled John Rankin over inside the box.
Ciftci coolly converted and it was almost 2-0 a minute later when Ryan Dow slipped behind the defence only for Craig Samson to block his goal-bound effort.
United were temporarily halted in full flow when Magennis pounced on a loose ball in the box, with Radoslaw Cierzniak all at sea as the ball trickled past him and over the line.
However, it was soon 2-1 to the visitors. Anier quickly latched on to Chris Eskine's through ball and his shot appeared to take a slight bobble over the outstretched hand of Samson.
Killie's Mark Connolly and Magennis and Dundee United's Callum Morris all went close with headers in what was proving to be an open game.
And Locke's side found the leveller following a howler from Cierzniak.
Johnston barely managed any power on his shot, but the goalkeeper somehow let it slip past him and over the line.
It was now the home side in firm control, and Tope Obadeyi and Magennis both had chances to put them ahead and Eccleston fired over after replacing Alexei Eremenko.
Just as it looked as if Dundee United would hold on for a point, Clingan found the net right at the death.
- 22WestlakeBooked at 23mins
- 29PascaliBooked at 83mins
- 10JohnstonSubstituted forCairneyat 86'minutesBooked at 87mins
- 19SlaterSubstituted forHamillat 73'minutes
- 20EremenkoSubstituted forEcclestonat 86'minutes
- 14MorrisSubstituted forSparkat 45'minutesBooked at 67mins
- 30AnierBooked at 35minsSubstituted forMuirheadat 73'minutes
- 17ErskineSubstituted forSpittalat 57'minutes
- Stephen Finnie
- Shots on Target
Second Half ends, Kilmarnock 3, Dundee United 2.
Goal! Kilmarnock 3, Dundee United 2. Sammy Clingan (Kilmarnock) right footed shot from very close range to the top right corner.
Paul Cairney (Kilmarnock) wins a free kick in the attacking half.
Foul by John Rankin (Dundee United).
Tope Obadeyi (Kilmarnock) wins a free kick in the attacking half.
Foul by Ryan McGowan (Dundee United).
Attempt missed. Nathan Eccleston (Kilmarnock) right footed shot from the centre of the box is close, but misses to the left.
Paul Cairney (Kilmarnock) is shown the yellow card.
Foul by Paul Cairney (Kilmarnock).
Charlie Telfer (Dundee United) wins a free kick in the defensive half.
Substitution, Kilmarnock. Paul Cairney replaces Chris Johnston.
Substitution, Kilmarnock. Nathan Eccleston replaces Alexei Eremenko.
Jamie Hamill (Kilmarnock) wins a free kick in the attacking half.
Foul by Ryan McGowan (Dundee United).
Foul by Chris Johnston (Kilmarnock).
Blair Spittal (Dundee United) wins a free kick on the left wing.
Manuel Pascali (Kilmarnock) is shown the yellow card.
Foul by Manuel Pascali (Kilmarnock).
(Dundee United) wins a free kick in the attacking half.