Simon Murray's winner was his eighth goal of the season
Dundee United moved level on points with Hibernian at the top of the Championship after eventually overcoming 10-man Dunfermline.
The visitors had to alter their game plan after Nate Wedderburn was shown a straight red card in the first half.
United missed with a series of long-range efforts before finally making a late breakthrough.
With 11 minutes left, striker Simon Murray turned the ball in from a corner to secure a vital win.
It was the Tangerines' sixth in a row in all competitions, and extended their unbeaten run to eight games.
The game was initially a test of United's patience. They had faced Dunfermline twice this season already, winning on both occasions, and the visitors sought to be organised, industrious and difficult to break down.
The approach was practical, given United's recent form and the fact they were playing with a certainty that their play would eventually deliver a goal.
They needed that faith, though, since they were restricted in the first half to a Scott Fraser shot skipping wide and a Murray effort bouncing off the legs of Dunfermline goalkeeper Sean Murdoch.
The visitors, second bottom of the Championship, were content to build a sense of reassurance. Industry was the priority, although they did carry a threat when Nicky Clark broke away on a counter-attack and struck a left-foot effort straight at United keeper Cammy Bell.
Nate Wedderburn's red card left the Pars facing the whole of the second half with 10 men
The game was finely balanced when Wedderburn suffered a moment of rashness. He launched himself, two-footed and off the ground, at Tony Andreu, with referee Don Robertson immediately issuing a red card.
Dunfermline looked to dig in after the interval, stiffening their midfield with substitute Rhys McCabe, whilst United were reliant on the shrewd promptings of Andreu, Willo Flood and Fraser. The latter pulled a shot wide after a sustained period of pressure.
With Murdoch being booked for time-wasting, it was evident how Dunfermline were looking to see out the game. They occasionally broke upfield, though, and Kallum Higginbotham almost opened the scoring as he shot across the face of goal.
The Pars thought they had engineered an opportunity to break the deadlock when United defender Mark Durnan barged Clark out the way of the ball as he ran into the box, but the referee was unmoved by the penalty claims.
Dunfermline's resistance was eventually broken though when a corner dropped to Murray at the back post and he clipped it high into the net.
Post-match reaction:
Dundee United boss Ray McKinnon: "It was a scrappy game, there wasn't any fluency and we had to be very patient. The guys are learning that patience is the key, they kept going about their business well and squandered a few half chances, but ultimately they got their reward."
"We were just about to take Simon [Murray] off and bring Blair Spittal on. He's got himself back in the team and he tends to pop up with a goal here and there, so I'm delighted for him."
On the red card: "I was only 20 yards away and I thought it was a really bad tackle [by Wedderburn]. Tony Andreu's really fortunate to not have a serious injury, so the referee got it spot on."
Dunfermline boss Allan Johnston: "You can see why the referee's given [the red card]. [Wedderburn]'s slipped and his foot's come up. But it's not meant if you know Nat, he's not that type of payer
"It was an excellent performance and even when we went down to 10 men, I thought the boys battled really well, they gave everything. If they keep playing that, we'll not be far away.
"We had a couple of chances and we don't get the penalty. It's a clear barge by Durnan on Nicky Clark and you can't get away with doing that in the box. I don't know how the referee's missed it because he's only five yards way."
