Celtic's hopes of going through an entire Bank of Scotland Premier League campaign unbeaten were crushed by an entirely unexpected home defeat at the hands of Aberdeen.

Dons manager Steve Paterson had confessed just minutes before kick-off that all he had been hoping for was a defeat that was not too painful for his injury-ravaged side that featured nine players under 21.

But when substitute Bryan Prunty, the former Celtic reserve, cancelled out Henrik Larsson's 15th-minute opener the stage was set for an upset no-one had been predicting.

The Dons rode their luck and won it at the death with a fine break that saw Australia international David Zdrilic slot past David Marshall.

It was the first time Celtic had been beaten in front of their own fans in 77 games, when Ajax had won a Champions League qualifier in August 2001.

With the title having been wrapped up with Sunday's win at Kilmarnock, there was hardly a competitive edge to the game and the fact that the trophy would not be presented until next month and the news that Lisbon Lion Ronnie Simpson, the goalkeeper, had died meant there was no carnival atmosphere before kick-off.

Celtic attacked regularly against nervous opponents and so jittery were the Dons that Larsson's 15th-minute goal had seemed a long time coming.

Momo Sylla set it up with a flick high over the Dons defence and the Swede had no difficulty slotting past David Preece for his 36th goal of the season and the champions' 99th in the campaign.

But Preece guessed Larsson's intentions when the striker tried to take the ball past him with a trademark sideways drag.

The Dons also had to make a change before the half-hour mark when Steven Tosh was replaced by Prunty.

But they recovered from their initial nervousness to create a couple of decent chances that were clues to the game's eventual surprise ending.

Scott Muirhead robbed a dithering Didier Agathe before curving a pass across the box that Foster, the 19-year-old striker, was inches away from converting.

Then Prunty was given what he had always wanted during his time at Parkhead - a sight of both posts and the defence nowhere - but volleyed so off target the ball hit Jackie McNamara, who had surrendered possession in the first place.

Paul Sheerin tested the recalled Marshall with a long-range effort as Aberdeen's confidence levels swelled visibly.

But Preece was still required to make a smart tip round at his near post to deny Neil Lennon and rookie centre-back Stephen McManus was only just too high with a rasping drive.

Celtic made a change at the break with Jamie Smith coming on for Agathe and within five minutes McNamara had limped off to be replaced by Bobo Balde.

Celtic were content to meander along happily until Prunty shocked them with a 56th-minute equaliser.

The impressive Muirhead was the man who made it happen with a low ball in from the left that neither Marshall or a defender could reach and there was Prunty at the back post to apply a close-range finish. He celebrated in style near a corner flag.

Celtic manager Martin O'Neill made a third and final change in the 67th minute when he sent Liam Miller on for McManus, who had performed well, in the hope of some extra creative spark being added.

The Manchester United-bound midfielder immediately forced Preece into a low save with an effort from outside the box.

Preece made a hash of two successive corners and needed Sheerin to make a goal-line clearance after Balde had seized on a loose ball in the box when the goalkeeper failed to collect the second.

But the Dons were to have the final say and, after Muirhead had passed up a great chance in the final minute by blasting over, Zdrilic showed him how it was done by getting the better of Paul Lambert in a race for a long ball and slotting past Marshall.

Teams

Celtic Marshall, McNamara (Balde 49), Varga, McManus (Miller 67), Agathe (Smith 45), Lennon, Lambert, Petrov, Wallace, Larsson, Sylla.

Subs Not Used: McGovern, Beattie.

Goals: Larsson 16.

Aberdeen Preece, Higgins, Rutkiewicz, Muirhead, Morrison, Tosh (Prunty 23), Heikkinen, Sheerin, Buckley, Zdrilic, Foster.

Subs Not Used: Esson, Souter, Stewart, Donald.

Booked: Sheerin.

Goals: Prunty 56, Zdrilic 90.

Att: 51,000

Ref: I Brines (Scotland).