A Kris Boyd-inspired Kilmarnock made it two wins on the trot as Hearts were cast further adrift at the bottom of the Scottish Premiership.
Boyd showed good composure to shoot low past Jamie MacDonald for his first goal on 16 minutes.
Callum Paterson came close to heading a Hearts equaliser after the break at a rain-lashed Rugby Park.
But Boyd showed class to cleverly lift his second strike over MacDonald and take Killie up to 10th place.
Allan Johnston's men climb above St Mirren and are now 16 points clear of Hearts, who are themselves 15 points short of the Buddies.
Therefore, the discord at Rugby Park relents - on the pitch at least.
During the first-half, the majority of Killie fans held up red cards and shouted "we want Johnston out" in unison as a protest against their chairman Michael Johnston.
His stewardship of the club seems something they want to end no matter what results are.
With the task Gary Locke's administration-hit Jambos have this season, utilising the experience of someone like Ryan Stevenson is paramount.
The former Ipswich forward was only getting back into the swing of things since returning from a lengthy lay-off and his first-half departure due to injury was a huge blow.
Stevenson's importance was highlighted when he created the game's first chance out of nothing, curling a right foot shot from the corner of the box which Killie keeper Craig Samson clawed away.
From there, Kilmarnock settled into the match and quickly went in front.
Boyd ignored the offside shouts for the through-ball that found him and ran into the box to complete his task, which was shooting low past Hearts goalkeeper MacDonald after calmly checking inside Danny Wilson.
Having the trickery and creativity of young winger Chris Johnston back in the side is clearly a boost for Killie.
His approach play was almost topped off by Barry Nicholson, but the former Aberdeen midfielder's hooked effort went over the crossbar.
The hosts lost Darren Barr to a nasty looking head knock but they continued to look the most menacing as the rain teemed down before the interval.
Both Michael Gardyne and Johnston had shots well blocked in the box, the latter's by a fantastic reaction save by MacDonald.
Paterson, on for Stevenson, had chances to equalise for Hearts either side of half-time with a flick and a header.
As Killie began to turn the screw, MacDonald had to be at his best once again to beat away Sean Clohessy's near-post drive. But the pressure would soon pay off.
Boyd chested down Jeroen Tesselaar's free-kick from deep and lifted it over the onrushing MacDonald in style to give Kilmarnock a two-goal advantage.
Dale Carrick came close to immediately reducing that lead before Killie went up the park once more and Johnston's rising shot was tipped over by MacDonald.
The home side absorbed the odd attack Hearts had left to offer and, fittingly, Boyd was given a standing ovation when substituted with a couple of minutes remaining.
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