Dundee United struck late to deny 10-man Dundee victory at Tannadice.
Gary Irvine's first-half dismissal for catching Richie Ryan with an arm gave the visitors an uphill task.
But it was John Brown's side who took the lead when Ryan Conroy blasted the ball high into the net midway through the second period.
United pressed for a leveller and were rewarded in the 89th minute when Michael Gardyne converted Jon Daly's headed knock-down to seal a point.
Dundee remain unbeaten in the Scottish Premier League since Brown took charge in February and the Dark Blues now trail St Mirren by 13 points at the foot of the table. United move level with sixth-place Hibernian.
Jackie McNamara's men made the more determined start, Daly and Rory Boulding both firing wide.
Gary Mackay-Steven had been taken out by some heavy challenges and, when referee Bobby Madden finally lost patience, Jim McAlister received a booking.
Tempers flared again when Irvine led with his arm in a jump with Ryan and the full-back was shown a straight red card, much to his team-mates' dismay.
Brown took action, withdrawing midfielder Nicky Riley and sending on defender Kyle Benedictus.
The hosts tried to make their advantage count and Barry Douglas' inviting centre was headed against the crossbar by Mackay-Steven.
Mackay-Steven seemed eager to make an impression ahead of his first involvement with the Scotland senior squad and the winger weaved his way into the box before forcing a solid stop from Simonsen, the keeper making his debut after joining Dundee on a short-term deal.
Gary Harkins, who had been moved from midfield into a lone striker role, almost gave the Dens Park side the lead with a low, trundling effort at the end of a bustling run towards the edge of the box.
Scrappy play restricted chances after the break with Conroy's free-kick held by Radoslaw Cierzniak and Daly heading off target at the other end.
However, Dundee made the most of a break on the left and Brian Easton's low centre was taken superbly by Conroy before the winger's powerful shot left Cierzniak helpless.
United responded and Daly was denied by Simonsen before chipping the rebound over.
And the pressure finally told when the Tannadice captain nodded a long ball into the path of Boulding's replacement Gardyne, who lifted the ball over the keeper with a crisp finish.