Lee Erwin scored one and set up another at Fir Park to hand Kilmarnock a seventh consecutive defeat which keeps them in danger of falling into the play-off position.
Erwin twice twisted and turned in the box to brilliant effect in the first half, his shot leading to Scott McDonald netting the opener on the rebound before firing home the second himself.
Kilmarnock made a game of it when Josh Magennis netted just after the break but Motherwell substitute Lionel Ainsworth sealed the points on a last-minute counter-attack.
The win puts Motherwell three points behind Killie and Ross County, who host St Mirren on Saturday, but the Lanarkshire side have an inferior goal difference to both.
Darryl Westlake, Jamie Hamill, Paul Cairney and Lee Miller had come back into the Killie team as Gary Locke tried to stop the rot with experience but the club’s record run of defeats continued.
It might have been different if they had taken a chance inside two minutes though when Stephen Pearson missed a Magennis cutback, but George Long got down to stop Cairney’s shot.
Long blocked a Magennis shot at his near post as Motherwell made a nervous start. They were over-hitting hopeful balls forward and failing to capitalise on a number of corners but they might have had a penalty when Westlake appeared to move his hand towards a cross.
McDonald headed over Marvin Johnson’s cross as Motherwell continued to press and Erwin provided the badly-needed creativity in the 26th minute when he beat two men just inside the box before firing a powerful left-footed shot. Craig Samson got down well to stop it but McDonald was on hand to force it over the line.
Lee Ashcroft missed a good chance to level when he sent a free header wide from Cairney’s corner and Motherwell were soon back on the attack with McDonald just unable to meet Johnson’s powerful cross.
Erwin doubled their lead in the 38th minute after latching on to Steven Hammell’s ball down the left after the full-back had put in an excellent challenge on Magennis. Erwin made the ball his in a chase with Ashcroft before turning the defender inside and out and firing home from 12 yards.
Samson saved Johnson’s near-post shot and McDonald’s header as Motherwelllooked to add to their tally before the interval, which allowed Locke to make a double switch.
Greg Kiltie and Tope Obadeyi came on for Sammy Clingan and Rory McKenzie and Kilmarnock made the livelier start to the half, getting the goal they needed to trigger the nerves in the home ranks in the 53rd minute.
Hamill’s corner caused panic with Long all over the place as the ball was headed back and forth across the goalmouth and Magennis eventually forced home from close range.
The game was on a knife-edge and tempers began to fray with Manuel Pascali booked for a bad foul on Johnson before Hamill and Pearson were booked following an altercation.
The Kilmarnock central defence soon misjudged a high ball to allow Conor Grant a chance but Samson touched over his strike.
Motherwell were being pushed back as the final 10 minutes approached but they managed to turn the tide. Erwin shot not far over on the break and McDonald curled a free-kick not far wide before McDonald set up Ainsworth to turn inside and drill home.
Killie pushed forward in injury-time but left a gap which McDonald almost exploited only for Samson to save