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Kilmarnock started the brighter, though Tony Watt passed up a glorious chance from close range for Hearts.
The home side took the lead when Souleymane Coulibaly curled a shot in from distance wide on the right.
Steven Smith then added a sublime second to seal the three points when he lobbed goalkeeper Jack Hamilton from 20 yards out.
Watt is a difficult player to get the ball off, but his finishing is one that needs improving. He'd only scored once this season but he should have doubled his tally in the fourth minute. He started the move with mazy play in the midfield before releasing the pass.
When it eventually arrived at Robbie Muirhead wide on the left the former Killie player delivered the perfect cross for Watt two yards out. But instead of volleying the ball into the net he managed to fluff his effort by only killing the ball and allowing goalkeeper Jamie MacDonald to smother.
Souleymane Coulibaly is gradually becoming the Kilmarnock talisman. Twice he had decent efforts before he did give the home side the lead. His first was a header which was blocked by his team-mate Nathan Tyson, his second a 25-yard free kick which curled inches wide of Jack Hamilton's right hand post.
It was third time lucky but it was more than fortunate it was another spectacular effort.
The Ivorian striker showed all his close control skills holding off challenges at the right edge of the penalty box. As he stumbled he quickly regained his balance to elude the tackle from Faycal Rherras then from 16 yards on the angle he curled a superb shot with his left foot which flew past the Hearts 'keeper into the right hand corner of his net for his ninth goal of the season.
Coulibaly came so close to adding a second before the interval, this time showing terrific spring in his legs to rise high six yards out to head goalbound a Tyson cross. However, Hamilton did well to turn away the striker's effort.
Muirhead had a 30 yard free kick which stung the hands of MacDonald who gathered at the second attempt, while at the other end Jordan Jones flicked a volley wide of the target.
Lee Clark has praised Rory McKenzie's performances in recent weeks and his harrying in an advanced central midfield role ensured the Hearts defenders were not getting time on the ball. He hit a left foot shot which clipped the bar before going over and then produced the assist for Killie's second goal.
McKenzie's tenacious play saw him gather possession midway inside then Hearts half and as he turned he spotted Smith advancing in a central area. The midfielder played the ball into his captain's path and he duly delivered the perfect finish. Smith's left foot curling strike into the top left hand corner of the net from 25 yards showing it's not only Coulibaly who can produce the spectacular.
Substitute Bjorn Johnsen had a chance to pull a goal back for Hearts, but he, like the strikers he replaced, could not provide a composed finish with only the goalkeeper to beat from six yards.
Kilmarnock's form at home has been poor recently but this victory - only their fifth in their last 28 top flight matches - may well have given them a welcome boost for the rest of the campaign.
Kilmarnock's Lee Clark: "I'm absolutely delighted. From the first whistle to the last we were outstanding as a team and individually some brilliant performances, but as group superb.
"We've won by two but we could have won by more.
"Rory McKenzie, Steven Smith and Gary Dicker set the tone when we had to press and also when we had to come off Hearts and get a good shape.
"We scored two wonderful goals and I'm absolutely delighted with the three points.
"Souleymane Coulibaly is a real showman. The fans love him. He's going to have his own montage of goals-of-the-season.
"The manner of the win against quality opposition tells me and it tells the players that as long as we stick to what we're about then we can get results home or away."
Hearts' Robbie Neilson: "The performance is disappointing but the biggest issue for me is we had that opportunity to go into second place and put pressure on Celtic and Aberdeen and we didn't manage to take it. If we want to compete at the top of the league when we get that opportunity we need to grasp it.
"Credit to Kilmarnock they pressed us really well and we didn't deserve to take anything out of the game. You have to compete, you have to turn teams and we were too easy to play against tonight.
"We have to move on to Inverness and try and rectify a poor display."
Match ends, Kilmarnock 2, Heart of Midlothian 0.
Second Half ends, Kilmarnock 2, Heart of Midlothian 0.
Foul by Callum Paterson (Heart of Midlothian).
Souleymane Coulibaly (Kilmarnock) wins a free kick in the attacking half.
Jamie Walker (Heart of Midlothian) wins a free kick on the left wing.
Foul by Greg Taylor (Kilmarnock).
Foul by Jamie Walker (Heart of Midlothian).
Adam Frizzell (Kilmarnock) wins a free kick on the left wing.
Attempt missed. Igor Rossi (Heart of Midlothian) left footed shot from outside the box is too high.
Substitution, Kilmarnock. Kris Boyd replaces Nathan Tyson.
Substitution, Kilmarnock. Adam Frizzell replaces Jordan Jones.
Substitution, Heart of Midlothian. Prince Buaben replaces Perry Kitchen.
Attempt blocked. Perry Kitchen (Heart of Midlothian) right footed shot from the left side of the box is blocked.
Delay in match Perry Kitchen (Heart of Midlothian) because of an injury.
Perry Kitchen (Heart of Midlothian) wins a free kick on the right wing.
Foul by Rory McKenzie (Kilmarnock).
Corner,  Heart of Midlothian. Conceded by Greg Taylor.
Attempt missed. Jordan Jones (Kilmarnock) right footed shot from outside the box is close, but misses to the left from a direct free kick.
Perry Kitchen (Heart of Midlothian) is shown the yellow card for a bad foul.
Foul by Perry Kitchen (Heart of Midlothian).
Jordan Jones (Kilmarnock) wins a free kick in the defensive half.
Arnaud Djoum (Heart of Midlothian) wins a free kick in the defensive half.
Foul by Rory McKenzie (Kilmarnock).
Jamie Walker (Heart of Midlothian) wins a free kick in the defensive half.
Foul by Steven Smith (Kilmarnock).
Attempt saved. Bjorn Johnsen (Heart of Midlothian) right footed shot from the centre of the box is saved in the centre of the goal.
Goal!  Kilmarnock 2, Heart of Midlothian 0. Steven Smith (Kilmarnock) left footed shot from outside the box to the top right corner. Assisted by Rory McKenzie.
Foul by Jamie Walker (Heart of Midlothian).
Souleymane Coulibaly (Kilmarnock) wins a free kick on the left wing.
Robbie Muirhead (Heart of Midlothian) is shown the yellow card for a bad foul.
Foul by Robbie Muirhead (Heart of Midlothian).
Greg Taylor (Kilmarnock) wins a free kick on the right wing.
Igor Rossi (Heart of Midlothian) wins a free kick on the right wing.
Foul by Nathan Tyson (Kilmarnock).
Attempt saved. Jamie Walker (Heart of Midlothian) right footed shot from the left side of the box is saved in the bottom left corner.
Attempt missed. Steven Smith (Kilmarnock) left footed shot from outside the box is too high from a direct free kick.
Igor Rossi (Heart of Midlothian) is shown the yellow card for a bad foul.
Foul by Igor Rossi (Heart of Midlothian).
Nathan Tyson (Kilmarnock) wins a free kick in the defensive half.
Attempt blocked. Robbie Muirhead (Heart of Midlothian) right footed shot from the centre of the box is blocked.
Hearts passed up the chance to move second in the Premiership as they fell to defeat by Kilmarnock at Rugby Park.