An incredible gift from Partick Thistle left Dundee United’s Nicky Clark with a tap-in to win this Scottish Cup tie.
The Tangerines suffered a shocking first half and trailed to Scott Tiffoney’s 25th-minute header for the League One side.
Lawrence Shankland grabbed an equaliser on 78 minutes then it was left to Clark to punish some shocking defending from the visitors and prevent extra-time being played.
The match took a bit of time to settle in the spring sunshine and the first opening fell to United’s Jeando Fuchs, whose shot from the edge of the box was blocked.
Up at the other end, Thistle’s Tiffoney pinged a 20-yard drive past the post.
Some defensive jitters almost cost United when Luke Bolton’s header back to goalie Deniz fell short. The visitors claimed for a penalty as Shea Gordon tried to reach the loose ball but clashed with the keeper. Referee Steven McLean saw nothing untoward and, rightly, waved play on.
Partick were on top, though, and it wasn’t a shock when they took the lead on 25 minutes.
The goal was a shambles from a United perspective, with a long throw-in from Ciaran McKenna allowed to reach their goalmouth and Tiffoney had time to wrong-foot Deniz with a header from just a few yards out.
Just after the half-hour, United striker Shankland seemed to have been sent clean through on goal by an Ian Harkes pass but he was ruled offside.
United’s Adrian Sporle had a half-chance with a header just before the break but it was Partick who should have burst the net withe their own opportunity.
The culprit was former Tannadice frontman Brian Graham, who looked set to tap in a Gordon cross in at the back post but somehow sent it wide.
United were all over the place at the back and Gordon clipped the ball over the United bar when he should have done better.
It was a terrible first 45 minutes for the Tangerines and they were put out of their misery when the half-time whistle was blown.
The home team clearly heard some strong words from manager Micky Mellon at the break and were on the front foot at last.
In quick succession, Shankland’s strike was blocked then Marc McNulty’s shot was deflected over the bar.
Shankland looked certain to level on 54 minutes when played in by a McNulty but Wright stuck a leg out and made the save.
Withe the hosts piling on the pressure, just seconds later McNulty had a go and the home players claimed the ball had gone over the goalline before being cleared by Stuart Bannigan, who then blocked Mark Reynolds’ attempt on the rebound. United boss Mellon was booked for comments made in the aftermath.
United brought on Logan Chalmers and Clark as they tried to save themselves.
Clark got on the end of a Robson cross from the left but couldn’t control the ball and it ran out for a goalkick.
The Tangerines had the Jags pegged back and they deserved their leveller on 78 minutes.
Sub Chalmers had a part in the move, sending the ball to Sporle. The Argentinian cut the ball back and it made its way through the legs of defender Mouhamed Niang to Shankland eight yards out. He spun and then poked his shot into the net to make it 1-1.
Some trickery from Shnakland down at the tunnel corner flag should have led to a United goal when he played the ball on to sub Pater Pawlett, who had replaced McNulty but the midfielder’s touch was poor.
There then came calamity for the League one side when they threw the tie away in stoppage-time.
Clark was the scorer but he had an empty net to tap in to.
United skipper Reynolds fired a ball forward that landed between Mouhamed Niang and his keeper. Clark seemed to push the Jags player, who then collided with goalie Wright. That left the stage clear for the sub to score the most dramatic of winners.
Dundee United: Deniz, Sporle, Reynolds, McNulty (Pawlett 86), Edwards, Robson (Chalmers 62), Butcher, Bolton, Harkes, Shankland, Fuchs (Clark 67). Subs not used: Siegrist, Connolly, Appere, Bisland, K. Smith, Walker.
Partick Thistle: Wright, McKenna, Foster, Niang, Brownlie, Docherty, Cardle (Murray 57), Bannigan, Graham (Rudden 81), Gordon, Tiffoney (Penrice 74). Subs not used: Sneddon, Lyon, Rodden, Williamson, MacIver, Ocholi.
Referee: Steven McLean.