Ayr sank Gretna's 100 per cent home league record of 22 consecutive wins.
And Gretna had to battle from behind to claim a point. But in the final seconds only the width of a post denied free-scoring Kenny Deuchar a match winner.
Ayr grabbed two goals inside three minutes against out-of-sorts Gretna midway through the first half.
A well-worked 23rd minute free-kick was helped on to Gareth Wardlaw, and although Alan Main got both hands to his shot, the ball spun up and into the net.
Then Chris Robertson climbed above the Gretna defence to meet Douglas Ramsey's free- kick with a powerful header into the bottom corner of the net.
Gretna, so impressive in midweek cup action against SPL side Dunfermline, made a couple of changes 10 minutes into the second half, bringing on Andy Aitken and Gavin Skelton.
And, in the 66th minute, they pulled a goal back from a Skelton corner. Ayr keeper Mark McGeown kept out an Aitken header and a David Bingham flick was headed off the line, but Derek Townsley bundled the ball in.
McGeown saved bravely at James Grady's feet as Gretna pressed for an equaliser, but had no chance when it came after 79 minutes.
Ayr substitute Chris Strain dwelt too long on a cross by Steve Tosh, and Skelton nipped in to steal the ball and steer it home.
Afterwards, Gretna manager Rowan Alexander said: "We told them at half time to roll up their sleeves up and win the battle."
Ayr manager Robert Connor admitted he was disappointed at having to share the points.
"It's a great result for us but everyone in the dressing room is disappointed. The way the game went I felt we could had had more," he said.