Dave Bolland supplied the lone goal in the fourth round of the shootout, as the Chicago Blackhawks overcame blowing a two-goal lead in the third period to edge the St. Louis Blues, 4-3, at the United Center.
Andrew Brunette and Patrick Sharp scored in the third period for Chicago, which snapped a two-game winless streak and notched its sixth win in eight games overall.
The Blackhawks could become the fifth Western Conference team to clinch a playoff spot if Phoenix loses to San Jose in regulation later Thursday.
St. Louis tied the game on goals from Jason Arnott and David Perron.
The point earned in the shootout gives the Blues 106, one more than the New York Rangers in the race for the Presidents' Trophy.