Patient Simon Murray was the hero for Dundee United as his late winner moved them joint top of the Championship with title rivals Hibs.
Murray struck for Ray McKinnon’s men on 79 minutes to finally break down ten-man Dunfermline in a tense affair.
The 24-year-old struck for the third time against the Pars this season after they had midfielder Nat Wedderburn red-carded just before half-time for a crude challenge on Tony Andreu.
United are now unbeaten in eight games and have won five on the bounce as they turn up the heat on the league leaders.
United and Dunfermline meet again in Saturday’s Irn-Bru Challenge Cup quarter-final at East End Park.
It remains to be seen whether last night’s bad feeling will linger.
Dunfermline, who remain in ninth place, started brightly, with Kallum Higginbotham getting into several good positions in the opening 15 minutes, linking with Nicky Clark and Farid El Alagui.
Dundee United’s young midfielder, Charlie Telfer, produced a fine corner for William Edjenguele’s towering header to force goalkeeper Sean Murdoch to stretch and keep the ball from looping under the bar.
Then Dunfermline responded with a counter attack which saw Clark draw a save from Bell with a raking shot.
However, the game spilled over into an ugly mess before the interval. Higginbotham lit the fuse when he was booked for dragging back Willo Flood, and then Higginbotham needed treatment after a tackle from Scott Fraser.
Nothing which had gone before, though, could excuse the dreadful lunge from Wedderburn on Andreu, moments later. Don Robertson, the referee, produced a straight red card for Wedderburn, and El Alagui and Tope Obadeyi were both booked as players confronted each other in a melee.
Murdoch proved he had not been distracted by all the mayhem, as he denied Murray just seconds before half-time by blocking the shot with his feet.
Dunfermline brought on Rhys McCabe for Joe Cardle for the second half but it was the hosts who maintained the greater threat, with Fraser skipping past two tackles before his shot from the edge of the box went narrowly wide.
Murray’s workrate is never in question but the United striker lacks composure, sometimes, as he illustrated in the 73rd minute when he advanced into the area and eschewed a pass to Cammy Smith before blazing his shot over the bar.
However, Murray’s determination paid off 11 minutes from the end. Fraser’s corner had caused panic in the Dunfermline box before it broke to Murray who hooked a left foot finish into the roof of the net and then milked the acclaim of the home support.