Two goals in the final two minutes from Motherwell's Scott McDonald destroyed Celtic's championship hopes and handed the SPL title to Rangers.
The Australian striker hooked in a wonderful shot with his back to goal from 12 yards and his deflected effort looped in just sixty seconds later.
Celtic opened the scoring on 29 minutes when a loose ball fell to Chris Sutton and he slammed it home.
The visitors squandered a host of chances and were caught at the death.
Rangers started the day two points behind Celtic but made up the ground with a 1-0 win at Easter Road.
Celtic knew a win would wrap the title and began the match at a furious rate of knots.
Play was scrappy on the muddy surface with Motherwell lacking composure and the visitors in too much of a hurry.
The lively Bellamy was denied the opener after exchanging passes with Sutton before firing a low shot which former Marshall spilled on to the post and behind for a corner.
John Hartson then sent in a powerful header but Marshall was right behind it.
The breakthrough came when Thompson dispossessed Richie Foran and charged forward to flash the ball across goal.
Marshall got down to beat the ball away but, with the home defence slow to react, Sutton lunged in to shoot home from eight yards.
Celtic relaxed after going in front but failed to threaten again before the half-time whistle.
Motherwell almost snatched an equaliser early in the second half when Stephen Craigan's header was blocked on the goal-line by Didier Agathe.
Hartson then squandered an opportunity to stretch Celtic's lead, heading a Thompson cross over from close range.
Bellamy broke free of the home defence but Marshall made a good one-handed save to stop the Welsh striker's low shot.
Marshall again did well to race from his goal and block at the feet of Hartson.
And the veteran ex-Celtic keeper made a first class save to stop Hartson's close range half-volley as Celtic poured forward.
There was a scare for Celtic when 'keeper Rab Douglas dropped a corner kick but Stanislav Varga was on hand to hook the ball to safety.
With Rangers in front at Hibs, Celtic supporters knew a goal for the home side would cost them dear and the tension inside the stadium was palpable in the final ten minutes.
And the travelling fans' worst fears were realised when McDonald controlled the ball on his chest and hooked the ball over his shoulder into the top corner of the net.
Worse was to follow for Celtic when McDonald squirmed past a couple of challenges and his shot hit a defender and looped over Douglas.
Motherwell: Marshall, Corrigan, Craigan, Kinniburgh, Fagan, Foran, Kerr, Fitzpatrick (Clarkson 88), Paterson, Scott McDonald, Hamilton (Britton 85). Subs Not Used: Corr, Higgins, Connolly, Keogh, Smith.
Booked: Foran, Craigan. Goals: Scott McDonald 88, 90.
Celtic: Douglas, Agathe, Balde, Varga, McNamara, Petrov, Lennon, Sutton, Thompson, Hartson (Beattie 75), Bellamy. Subs Not Used: Valgaeren, Lambert, Laursen, Marshall, Maloney, McGeady.
Booked: Bellamy. Goal: Sutton 29.
Ref: H Dallas