Alex Pietrangelo scored 2:11 into overtime after Jamie Benn pulled Dallas even late in regulation and St. Louis ended up tied with the Stars atop the Western Conference after the Blues' 5-4 win Saturday night.
It was the second straight night that the top spot in the West was on the line in Dallas after the Stars beat Chicago 5-2 with both teams tied atop the conference.
The Stars forced overtime with a 6-on-4 advantage in the final 2 minutes of the third period when Benn redirected Tyler Seguin's shot past Jake Allen.
The point for Dallas left both teams with 91 points with 12 games remaining. The Blackhawks have 88 points with 13 games to play.
Dallas' Jason Spezza had two goals for a six-game goal streak, the longest of his career.