Gavin Skelton's late goal gave Gretna victory over 10-man Hearts in their final SPL game before being relegated.
Hearts striker Gary Glen was sent off in the 25th minute after kicking out at Gretna's Craig Barr.
Both sides struggled for fluency on the poor Fir Park surface and Hearts looked lethargic for long spells.
Rostyn Griffths thought he had given Gretna the lead just before half-time when he converted McGill's cross, but it was chalked off for offside.
Gretna, who were playing their last SPL game with their long-term future in doubt, started the brighter of the two sides.
Nicky Deverdics went close for the hosts early in the game when he volleyed wide on the turn.
Hearts rarely threatened in the opening period, with Jamie Mole's low cross evading Deividas Cesnauskis when they did carve a decent move down the left.
Deverdics spurned a chance in the 15th minute when he sliced wide after Hearts defender Christos Karipidis missed a low cross by Rhys Meynell.
Glen lost his head in the 25th minute when he lashed out at Barr and received his marching orders from referee John Underhill.
Gretna continued to push forward and were unlucky when Danny Hall's drive from the edge of the box was blocked by team-mate Craig Barr following a corner.
Griffiths put the ball in the net following a McGill cross but Gretna's celebrations were shortlived as the effort was ruled out for offside.
Hearts pressed in the second-half and Artur Krysiak saved brilliantly to deny Kestutis Ivaskevicius.
The game looked destined to end goalless until Skelton flashed the ball past the helpless Steve Banks from 15 yards to secure an unlikely victory for the SPL basement side.
Gretna are relegated to Division One, but face an uncertain future after going into administration.
Hearts finish the season in eighth place, still looking for a manager to succeed caretaker boss Stevie Frail.
Gretna: Fleming, Barr, Griffiths, Hall, Naughton, McGill, Osman, Meynell, Skelton, Deverdics, Hogg. Subs: Krysiak, Murray, Fisher, Taylor, Robinson, Sharples, Schultz-Eklund.
Goal: Skelton 90.
Hearts: Banks, Thomson, Karipidis, Zaliukas, Wallace, Screpis, Kingston, Stewart, Cesnauskis, Mole, Glen. Subs: Ridgers, Ivaskevicius, Goncalves, McGowan, Rapnik, Palazuelos, Husband.
Sending off: Glen 25.
Att: 1,090
Referee: J Underhill
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