Halak turned aside seven shots in the third period, when the Blues registered goals by Alex Steen and T.J. Oshie to seal their fourth win in five contests.
Steen also notched an assist and Chris Stewart added a goal for the St. Louis.
Nikolai Khabibulin recorded 22 saves as Edmonton fell for the third time in four games.
2014: NFL Cheerleaders [PHOTOS]
UPI Sports Results for September 19, 2014