It took a late equaliser from Lee Wilkie to ensure United stayed in the hunt after it had appeared likely that Chris Porter's double would keep Well in the driving seat.
United started the game the better side with Willo Flood's shooting causing the home defence problems. One effort from the edge of the box forced Graeme Smith to tip the ball over his own crossbar.
Against the run of play the home side took the lead in the 17th minute. Stephen Hughes crossed into the box and the ball was flicked on by the head of David Clarkson for Chris Porter to head home from close range.
But just when it looked as though the home side would take a lead into the break, they were stunned by a strange equaliser.
Morgaro Gomis' cross was headed back into the six-yard box by Noel Hunt and, in a desperate effort to clear the danger, Stephen Craigan could only head the ball into his own net.
Motherwell responded well to the setback at the start of the second half when Porter once again headed home from close range, this time from a fiercely-driven Ross McCormack free-kick.
Both sides then struggled with the bumpy pitch and swirling wind and it was no surprise when United grabbed an equaliser with four minutes left.
Danny Grainger's long throw was headed on at the front post by Darren Dods for his central defensive partner Wilkie to head home at the far post.
Motherwell could have scored a winner in stoppage time as Clarkson pounced on Sean Dillon's slip. He ran through before sliding the ball into the path of Keith Lasley but the Motherwell sub could only fire into the side-netting from an acute angle.
The point gained probably leaves Motherwell in a better position than United in the race for the UEFA Cup spot as games start to run out.