Kelechi Iheanacho scored a penalty winner nine minutes into stoppage time after a video review, boosting Celtic’s Premiership defence thanks to a comeback win at Motherwell as the most dramatic title race in decades took another sensational twist.

Iheanacho slotted in a spot-kick after the former Hearts midfielder Sam Nicholson was penalised for handball after jumping to head the ball away. The ball appeared to hit his raised hand right in front of his head.

Another former Hearts player, Motherwell’s Liam Gordon, had appeared to hand his old club a massive advantage in the title race after netting an 85th-minute equaliser.

At that point, Celtic were heading into a final-game title decider needing to beat Hearts by three goals and they did not look like getting a winner until the referee, John Beaton, was called to the monitor by the video assistant, Andrew Dallas, as five minutes of stoppage time were coming to a close.

Beaton pointed to the spot and Iheanacho kept his cool to seal victory and spark a pitch invasion from the visiting fans.

Motherwell had been heading into Europe moments earlier but the penalty drama was compounded by Hibernian’s late winner at Ibrox and they will now need to avoid defeat at Easter Road on Saturday to secure fourth.

The victory means Celtic now face a simple equation on Saturday – they will win the title if they beat Hearts.

Martin O’Neill’s previous trip to Fir Park as Celtic manager saw his side lose the title in the closing stages of the 2004-05 season when Scott McDonald’s late double handed Rangers the glory. He looked set for more anguish in Lanarkshire as Motherwell, wearing their original blue colours to mark their 140th anniversary, dominated the opening stages.

Elliot Watt volleyed them ahead from 22 yards in the 17th minute and they threatened to carve Celtic open on other occasions. Panic was evident among the travelling fans as Celtic struggled to get going – and leaders Hearts scored twice at Tynecastle on their way to a 3-0 win – but they came into the game towards the end of the first half.

Daizen Maeda dragged a half-chance wide and soon found his range in the 41st minute as he fired in off a post after getting the break of the ball when Callum Slattery tracked back to tackle Yang Hyun-jun.

Arne Engels lobbed the ball off the crossbar before the break after Maeda had collided with the Motherwell goalkeeper Calum Ward following Callum McGregor’s lofted ball. Celtic pressed in the opening stages of the second half but were left space in behind and Slattery played Elijah Just down the left channel.

The New Zealand international turned inside Auston Trusty but lost balance slightly and McGregor got back to make a crucial tackle. Motherwell threatened again after a wonderful passing move but Slattery slipped as he looked set to shoot from 15 yards.

Benjamin Nygren produced a moment of magic to net out of the blue from 25 yards in the 58th minute, with Motherwell defending in numbers.

With goal difference no longer an issue as long as Celtic collected three points, the champions tried to keep their hosts at bay. They could not and the home side’s pressure built. Watt deflected a shot off the crossbar before Viljami Sinisalo grabbed Tawanda Maswanhise’s follow-up header on his line.

The Celtic goalkeeper made an excellent one-handed stop from Just, but was beaten by Gordon after Maswanhise was twice denied.

Motherwell looked the more likely team to net a winner in the following moments but there was another twist as Beaton was sent to the screen after the indicated five minutes of stoppage time had elapsed.