Fraser Murray netted his fourth goal in nine games as Kilmarnock earned a much-needed three points against 10-man Motherwell.
Murray capitalised on some slack defending to open the scoring midway through the first half, while Kofi Balmer was sent off following a VAR review, four minutes later.
Joe Wright’s 53rd-minute header set Killie up for a comfortable second half as they sealed a 2-0 win that kept them a point ahead of Dundee, who occupy the William Hill Premiership relegation play-off place.
Dundee’s victory over St Mirren kept Motherwell’s top-six hopes alive but possibly only for 24 hours.
The Steelmen need Dundee United to take something from Tynecastle on Sunday to allow them to move above Hearts if they beat Neil Critchley’s side at Fir Park in the final game before the split. Even then, they will need Ross County to get a result against St Mirren in Paisley.
Killie had seen their own top-six chances disappear with a 5-1 defeat against the Buddies the previous weekend and Derek McInnes made five changes after taking one point from a possible 15.
Defender Stuart Findlay made his first start since suffering an ankle injury six months ago, while goalkeeper Robby McCrorie was among those dropped.
His replacement, Kieran O’Hara, did not have a save to make until Andy Halliday trundled a shot his way, seven minutes into stoppage-time.
Motherwell played a significant part in their own downfall as the game turned on four minutes of action, after a scrappy start.
Ellery Balcombe touched Bobby Wales’ shot on to the post after Halliday slipped in front of his own box and Dan Casey’s clearance was picked up by Danny Armstrong.
The winger’s square pass cut through four Motherwell players including Balcombe before Murray knocked the ball into an unguarded net.
Balmer was soon sent off after referee Matthew MacDermid studied footage of his tackle on Murray. The centre-back won the ball but was ruled to have committed serious foul play with the follow-through.
Killie looked to exploit their numerical advantage. Findlay had a volley saved, Bruce Anderson miskicked from a good chance and both Murray and Wales had shots blocked after making space.
Anderson then had a header tipped over before Motherwell conceded another soft goal when Wright headed in Armstrong’s deep corner from a tight angle.
Killie lost Lewis Mayo to injury and the visitors were briefly down to nine men when Dom Thompson lost his temper and jumped on Armstrong after both players had been grounded by a challenge.
Thompson had to be dragged away from home substitute Robbie Deas as he walked towards the tunnel but he was halted by a VAR review and saw his punishment downgraded to a yellow card.
The left-back was soon substituted but none of Michael Wimmer’s changes could have any impact on the flow of the game.
Balcombe made good saves from Wales and substitute Calvin Ramsay after briefly delaying the game when he sprinted down the tunnel, while Killie waited to take a corner on his return.
