Peter Houston's men looked like winning their first home SPL clash since August when defender Gavin Gunning headed them into the lead inside two minutes, but an own goal from team-mate Brian McLean put paid to that as Steve Lomas' Saints side fought back to ensure a deserved share of the spoils.
United wasted no time in making their mark in this early kick-off when, in the second minute, Gunning made it 1-0 with a free header from Barry Douglas' inswinging free-kick.
Patrick Cregg's foul on Johnny Russell left the United forward nursing a head knock but presented the hosts with a perfect scoring opportunity. And Gunning could hardly believe his luck when the Saints defence stood still to allow the Irishman to rise unchallenged and direct a header downwards past Alan Mannus.
Saints seemed to be caught on the hop by the midday start, which came on the back of defeat away to Aberdeen the previous weekend.
But in the 16th minute, striker Steven Maclean turned neatly on the edge of the penalty area and his smart shot was well saved by Radoslaw Cierzniak in the home goal.
Midway through the first half, Cierzniak had to look lively to produce an impressive double save. Tam Scobbie's cross was nodded goalwards by Liam Craig only for Cierzniak to deny him with a fine diving stop. The rebound fell kindly for Craig but again Polish keeper Cierzniak proved equal to the task as he parried his effort wide for a corner.
In 33 minutes, United came within inches of increasing their lead. Rudi Skacel, who had earlier been booked, saw his shot from 12 yards parried by Mannus at full stretch. As the Saints defence stood stranded, Gunning tried to nip in at the far post to apply the finishing touch but just missed out on making contact and the visitors breathed a huge sigh of relief.
Two minutes later, Saints raced to the other end as Dave McKay and Peter Pawlett combined to set up Maclean, but his attempt at a bicycle kick inside the six-yard box did not quite come off.
Saints started the second half much the livelier side and were back on level terms in the 46th minute.
Gregory Tade released Pawlett and his jinking run left a couple of United defenders in his wake before squaring the ball across the face of goal. McLean was tracking back but in an attempt to clear his lines he had the misfortune of turning the ball into his own net beyond the helpless Cierzniak.
Suddenly United were facing that familiar scenario of failing to kill teams off which seriously looked like coming back to haunt them.
Just seconds after equalising, Saints went in search of another and almost got it when Craig swivelled eight yards out before driving a shot on target which Cierzniak did well to beat away.
With 10 minutes left, Gunning's header from Douglas' corner was cleared of the line by Patrick Cregg but it finished a draw.