Aberdeen claimed their second win on the trot at Celtic Park on an incredible night in Glasgow's east end.
Two goals inside the opening six minutes and an injury-time winner after Celtic had dragged themselves back on level terms allowed Jimmy Calderwood's side to return north with all three points and a bus load of smiling faces.
When they travel south once more to face Rangers at Ibrox on Sunday they can do so in the knowledge that Glasgow is no longer as seemingly impossible task.
It was a truly storming start by Aberdeen. Only five minutes had gone when they silenced the home fans for the first time in the evening.
Derek Adams put in a corner from the right and Fernando Pasquinelli angled his header in the direction of the far post. Darren Mackie took advantage of a startled defence to ensure the ball reached its target.
Within two minutes Celtic's hopes worsened. Neil Lennon's backpass prompted a dreadful error by David Marshall and Pasquinelli picked up the ball and walked it calmly into the net.
Within seconds Celtic started a long-term onslaught on the Dons goal. They got one back on the stroke of half-time, Chris Sutton laid the ball off to John Hartson and he scored with a low shot from 15 yards.
The equaliser came on 69 minutes from Stilian Petrov's assist, Hartson's powerful right-foot shot made its way under Ryan Esson, who had early replaced David Preece in goal.
Celtic seemed likely to take all three points, but Aberdeen scored a brilliant breakaway goal in stoppage time when sub John Stewart lobbed Stanislav Varga and calmly scored in the bottom left-hand corner of the net.
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