Kilmarnock substitute Bruce Anderson scored a 90th-minute equaliser to secure a 1-1 draw at Tynecastle as faltering Scottish Premiership leaders Hearts endured a fourth consecutive match without victory.
Lawrence Shankland's strike early in the second half looked like proving decisive for the Jambos until Anderson forced the ball home from close range to leave the home support shell-shocked.
The result allowed Celtic, who trailed by nine points in early November, to move level on points with Derek McInnes' side ahead of Sunday's top-of-the-table showdown at Parkhead.
On a night when Hearts paid tribute ahead of kick-off to chairwoman Ann Budge, who is bowing out after 11-and-a-half years at the helm, boss McInnes freshened his team up with five changes from Saturday's goalless draw at Motherwell, including handing Christian Borchgrevink and Alan Forrest their first starts since August.
Killie boss Stuart Kettlewell, whose side had not won in their previous seven matches, made four changes to the team that started Saturday's 1-1 draw at home to Dundee United, with Tyreece John-Jules in the starting line-up for the first
time since he arrived in October.
After a bright start from Hearts, their first notable chance came in the 15th minute but Shankland's attempted chip was clutched by goalkeeper Tobi Oluwayemi after good work by Cammy Devlin and Landry Kabore to tee him up on the edge of the box.
Killie threatened for the first time in the 28th minute when Brad Lyons pinged a 25-yard strike just over.
The hosts were struggling to convert their possession into clear opportunities, although they went close just after the half-hour mark when Kabore just failed to turn a tantalising Borchgrevink delivery over the line.
The visitors had the biggest chance of the first half, however, when James Brown somehow knocked wide of the gaping goal from six yards out after Greg Kiltie's shot was beaten out into his path by Hearts keeper Alexander Schwolow.
The breakthrough came four minutes after the interval when Kabore dummied a pass from Tomas Magnusson and Shankland ran clear to dink a lovely finish beyond Oluwayemi from just inside the box.
Shankland threatened again with a header at the back post before Magnusson headed Harry Milne's corner against the post.
Kabore and Shankland then sent efforts just wide as the Jambos tried to increase their lead.
Killie almost equalised in the 74th minute when substitute Marcus Dackers glanced a header against the crossbar from a Kiltie cross. David Watson then flashed a shot just wide as tension grew among the home support.
Hearts had further chances to kill the game, with substitutes Claudio Braga and Blair Spittal going close.
But the stuttering leaders were left stunned when Anderson pounced to knock the loose ball over the line after Schwolow allowed a Liam Polworth strike to squirm from his grasp.
