The teenage defender converted from two corners after his mistake led to Mark Reynolds putting the visitors in front just after the halfway mark in the Clydesdale Bank Premier League clash.
Celtic also had goalkeeper Lukasz Zaluska to thank as they moved eight points ahead of Dundee United in their quest to secure a Champions League qualifying spot.
Zaluska saved from Lukas Jutkiewicz as Motherwell carved out the best chance of the first half and, although Celtic eventually pushed their visitors back after the opener, the Pole made further important stops.
Celtic interim manager Neil Lennon made three changes following the Scottish Cup semi-final defeat with Georgios Samaras and Andreas Hinkel dropping out of the squad with Marc-Antoine Fortune benched. Mark Wilson, Niall McGinn and the fit-again Diomansy Kamara replaced them.
Celtic Park looked less than half full and, although the home players were afforded a good reception, there was a low-key atmosphere as Celtic enjoyed the bulk of possession without threatening until the 10th minute.
McGinn charged down Stevie Hammell’s clearance and crossed for Robbie Keane, but the ball was marginally behind the Irishman and he could not direct his header goalwards.
Motherwell lost Keith Lasley to injury a minute later with Giles Coke coming on, but they enjoyed a decent spell which culminated in Steve Jennings having a shot blocked from 20 yards.
Aiden McGeady saw an enterprising run foiled by Michael Fraser at the goalkeeper’s near post but the visitors came close in the 28th minute after Jutkiewicz had collected a long ball and turned Darren O’Dea. The on-loan Everton striker fed Jamie Murphy, whose shot from the edge of the box was spilled by Zaluska, but Scott Brown scrambled the ball clear as Jutkiewicz tried to turn home the rebound.
Motherwell created an even better chance in the 33rd minute when Murphy showed good skill before releasing Jutkiewicz in the right channel, but Zaluska came out to block the striker’s low shot from 15 yards.
Celtic broke moments later but Keane dragged a difficult chance wide after McGinn’s pass and Fraser comfortably held McGeady’s long-range effort.
Motherwell took the lead three minutes after the restart when Thompson could only divert Tom Hateley’s free-kick into the path of Reynolds, who finished from six yards.
Thompson took just two minutes to atone though when he turned the ball into Fraser’s bottom corner from 12 yards after Brown had headed down McGinn’s corner.
McGeady then shot just over from the edge of a crowded penalty box.
Motherwell almost shot themselves in the foot on the hour mark when Jim O’Brien lost the ball after Hateley’s short corner, allowing McGeady to break and send a diagonal ball into Keane, but Fraser blocked his shot.
Celtic moved ahead in the 78th minute when Lee Naylor curled a corner into the six-yard box and Thompson headed powerfully home.
Keane was not far away with a well-executed volley from 25 yards before Jutkiewicz limped off and Chris Humphrey came on.
Zaluska had more work to do but the three points were secured, which means Rangers cannot clinch the title at Tannadice tonight.
CELTIC: Zaluska, Wilson, Thompson, O’Dea, Naylor, McGinn (Fortune 76), Brown, N’Guemo, McGeady, Keane, Kamara. MOTHERWELL: Fraser, Hateley, Craigan (Saunders 56), Reynolds, Hammell, O’Brien, Lasley (Coke 11), Jennings, Murphy, Jutkiewicz (Humphrey 81), Sutton. Ref: I Brines (Scotland).
lNEWCASTLE all but secured the Coca-Cola Championship title as Kevin Nolan’s brace gave them a 2-1 victory at Reading. Nolan struck twice before the break to take his tally to 18 for the season and put Chris Hughton’s side nine points clear of West Brom.