Steve Crawford returned to haunt Dunfermline with a second-half strike to deny them victory.
The former Pars striker will never have scored an easier goal as he helped a Barry Robson header over the line after 72 minutes.
It denied Dunfermline a victory after they led through a goal late in the first half from Jesper Christiansen.
Crawford had a chance after just 25 seconds when he got his head to a cross from Mark Wilson but Derek Stillie dived to his left to save.
United started brightly and Robson had a free header at the near post from a Jim McIntyre cross but his flick just carried a yard wide of the far post.
Crawford had another chance after a mix-up in the home defence but he rushed his shot when he had time to do better.
But the home side hit back. Christiansen cut the ball back from the right for Gary Mason and his low shot struck the base of the post before bouncing to safety.
Barry Nicholson then came close with a 20-yard shot which whistled just wide of Tony Bullock's left-hand post.
Robson forced another save from Stillie with a right-foot shot as both sides went in search of the breakthrough.
Noel Hunt was booked for diving in the 34th minute when he tumbled in the box after a challenge from Lee Mair as the Dunfermline fans thought they should have had a penalty.
The incident seemed to fire up the Irish striker. Within seconds, he had galloped to the edge of the United box and struck a stunning shot which was only matched by the save by Bullock as he clawed the ball over his crossbar.
Dunfermline stepped up a gear towards half time and got their reward with a goal two minutes from the break.
Gary Dempsey's cross was not dealt with by the United defence and Hunt managed to divert the ball into the path of Christiansen who thumped the ball high into the net from just a yard out.
Dunfermline had another penalty claim when the ball seemed to strike Robson's hand in the box but referee Craig Thomson waved the appeals away.
Dundee United had to rely on a goalline clearance from Mark Kerr to prevent Scott Thomson scoring with a header after 62 minutes.
Four minutes later, Hunt had an unbelievable miss when he headed wide in front of an empty net after Lee Makel had flicked the ball on.
But Crawford equalised when Robson looped a header over Stillie and the striker helped the ball over the line.