T.J. Oshie scored the lone goal in the shootout, Jaroslav Halak stopped all three Chicago shooters in the extra session and the St. Louis Blues defeated the Blackhawks 3-2 on Thursday night.
David Backes scored a power-play goal for St. Louis, while Alexander Steen was credited with an even-strength score in regulation in the Blues' first road game.
Chicago's Marian Hossa scored on a breakaway and set up Brandon Pirri's first NHL goal in regulation.
All but one of the Blackhawks' (4-1-2) first seven games have been decided by one goal.
The Blues (5-1-0) started the season with five straight home games, and won the first four before losing 6-2 to San Jose on Tuesday.
Chicago's Corey Crawford made 26 saves and Halak had 27.