Mark Burchill last night accepted with alacrity the chance to replace Henrik Larsson as Celtic's talisman and goal scorer. His equalising effort in the 48th minute opened up the way for them to claim victory with an injury-time header by the Dane Morten Wieghorst.

The win was highly fortunate and it seemed, until the final act, that the club had not only lost their best player in France last week but also some degree of self belief.

Celtic were livelier in the second half and had the encouragement of Burchill's goal in the 48th minute. Reggie Blinker pushed the ball to his feet on the edge of the box and the teenager managed to wriggle clear of a couple of challenges before hitting a strong right-foot shot into the bottom of the net. He was also unlucky to have a later chance disallowed for offside.

A draw seemed inevitable until the third minute of stoppage time when Bobby Petta swung over a cross and Wieghorst headed in off post and bar.

Celtic's head coach John Barnes had taken the unusual step of relegating Craig Burley, Johan Mjallby and Lubomir Moravcik, all of whom played in Lyon, to the substitutes' bench. Instead he filled up the midfield with his fringe players Petta, Blinker, Morten and Stilian Petrov and in the first half they played like men not truly acquainted with each other.

Only twice before the interval did they threaten the Saints' goal. Petrov grazed a post with a swinging shot from 30 yards and Petta hit another rather tame attempt that was safely gathered in by the goalkeeper Alan Main.

The fans chanted: "Don't take Larsson away". And it was difficult to resist coming to the conclusion that his absence must have produced quite an aftershock. Celtic appeared to be a side doing little more than go through the motions, which was inexcusable given the tangible incentives in front of them this autumn.

In comparison the Saints were, by their standards, rather frisky. They did not enjoy too much possession but were comfortable enough on the ball. When they took the lead in the 29th minute it rather summed up Celtic's mood.

Paul Lambert, a captain who does not give the ball away for months on end, was ushered off it unceremoniously by Paul Kane in midfield. His forward pass found George O'Boyle, making his second start after a year out with an Achilles tendon injury, and he slipped it through to Nathan Lowndes, who calmly drew Celtic goalkeeper Jonathan Gould into the position where he wanted him before slipping the ball under his body for a fine goal.

It rather contrasted with Celtic's over-reliance on Gould's long kicks and the direct route to goal, which is hardly the way they have played traditionally.

St Johnstone: Main, McQuillan, Dasovic, O'Boyle, Kane, Lowndes (Simao 66), Bollan, Griffin, O'Halloran, McCluskey, McAnespie. Subs Not Used: Robertson, O'Neil, McBride, Thomas. Booked: Dasovic, McCluskey. Goals: Lowndes 29.

Celtic: Gould, Riseth, Tebily (Mjallby 90), Wieghorst, Stubbs, Lambert, Petta, Blinker, Petrov, Burchill, Viduka. Subs Not Used: Kharine, Burley, Healy, Moravcik. Booked: Blinker. Goals: Burchill 48, Wieghorst 90.

Referee: H Dallas (Scotland).