Liam Kelly's first-half penalty proved to be the difference as Kilmarnock overcame Hearts in a Boxing Day Scottish Premier League encounter.
The midfielder fired the hosts into the lead on 26 minutes, following Andy Webster's foul on James Dayton.
Hearts battled hard for an equaliser with Andy Driver and Mehdi Touil forcing saves from Cammy Bell.
And the Killie keeper also denied Callum Paterson after the substitute had gone through on goal.
Kilmarnock move up to sixth, while Hearts slip to ninth ahead of their final SPL fixtures of 2012 on Saturday.
Hearts were prominent in the opening quarter with Driver firing over and a deflected Ryan Stevenson blocked by Bell.
Killie, who had a Paul Heffernan goal disallowed for offside, stretched their visitors on the flanks and, from one such attack, Dayton was taken out by Webster in the box.
Webster's challenge on Dayton was punished with a penalty kick
Kelly marked his return from suspension with a confident low shot past Jamie MacDonald.
Gordon Smith thundered a half-volley into Bell's net moments later but a foul by Sutton in the build-up meant the goal did not stand.
The forceful runs of Dayton were tormenting Hearts and the midfielder flashed a shot wide after cutting in from the left.
Driver crossed for Smith to head wide before the break and and another weaving run by the winger in the second half ended with a shot that Bell tipped over.
Bell was then caught by Sutton as the forward slid in to try and convert a mis-hit Smith shot and the Hearts man was booked as the keeper received treatment.
The Killie stopper recovered and was called into the action again to block a fierce Mehdi Taouil volley.
Hearts responded angrily when Rory McKenzie went down in their box after no contact from nearby Ryan McGowan, with referee Steven McLean electing not to book the Killie player.
Paterson had replaced Smith and had an excellent chance to level when he escaped the Killie defence and raced through.
But the substitute shot a little too early and Bell got down well to make the save.
Killie's lead was looking ever more fragile as Hearts poured players forward and a Marius Zaliukas shot deflected narrowly wide of the hosts' goal.
The Hearts captain was perhaps fortunate to receive only a booking after clipping the heels of Heffernan as the forward sought to beat MacDonald to a threw ball.
Hearts mounted more pressure in the closing stages but Kilmarnock held firm to claim all three points.
Kilmarnock 01 Bell 04 Fowler 06 Nelson 23 McKeown 88 Sissoko Booked 08 Kelly 10 Dayton (McKenzie - 82' ) 15 Perez (Johnson - 37' ) 29 Pascali Booked 12 Sheridan 14 Heffernan (O'Leary - 90' ) Substitutes 17 Letheren 02 Tesselaar 05 O'Leary 38 O'Hara 11 Harkins 18 Johnson 24 McKenzie Heart of Midlothian 01 MacDonald 04 McGowan 06 Webster 26 Zaliukas Booked 29 McHattie 05 Barr (Novikovas - 70' ) 07 Stevenson 10 Taouil (Robinson - 85' ) 11 Driver 09 Sutton Booked 12 Smith (Paterson - 63' Booked ) Substitutes 21 Enckelman 15 Holt 19 McGowan 08 Robinson 18 Novikovas 33 Paterson 37 Carrick