Yet early in the second half Rangers incredibly found themselves two behind after Christian Kalvenes headed home to add to Noel Hunt's first half strike.
Chris Burke who had come on for the ineffective Karl Svensson immediately pulled one back before United substitute Steven Robb headed past his own keeper with ten minutes remaining to level the scores.
It was a pulsating match, though Rangers must still be wondering how they failed to win. Early on Charlie Adam's volley was parried out by the heroic Derek Stillie before his shot from the rebound was cleared off the line by Greg Cameron.
United stunned the home support when they took the lead. Hunt gathered Stuart Duff's cross before turning and hitting an unstoppable shot into the top corner. Stillie then denied a Rangers attack almost single-handedly with brilliant saves from Libor Sionko and Thomas Buffe and to add to the home side's misery Dado Pirso and Julien Rodriguez saw net-bound headers cleared off the line.
The visitors punished Rangers further early in the second half when the unmarked Kalvenes headed home a Barry Robson corner. Rangers responded immediately, as substitute Burke swept home a left-foot shot from 18 yards. Manager Paul Le Guen had sent on Kris Boyd and new signing Filip Sebo before the home side equalised rather fortunately.
Steven Smith's long diagonal cross was going nowhere when Robb headed back, not realising his keeper was behind him and both watched agonisingly as the ball rolled into the empty net.
There was still time for Stillie to produce another marvellous save to deny Sionko before United were able to claim a fortunate share of the points.