The Blues split their two games at the Tom Kurvers Prospect Showcase, as they lost 3-2 in overtime on Saturday night to the Blackhawks.
Oliver Moore scored the game-winning goal for Chicago 24 seconds into overtime.
Otto Stenberg and Anthony Kehrer scored for the Blues, and Will Cranley stopped all 13 shots he faced during his 30 minutes of action on Saturday night. Amateur tryout goaltender Matthew Koprowski allowed three goals.
Taige Harding and Ryan Mast also scored for the Blackhawks.
Stenberg scored just 1:18 into the game on Saturday night, finishing a feed from behind the net from Juraj Pekarcik. It was Stenberg's third point of the weekend, as he had two primary assists during Friday's 6-4 win over the Wild.
The Blues made subtle tweaks to their lineup against the Blackhawks.