The first of Dave Bolland's two goals came during a busy first period and gave the Blackhawks a 2-0 lead.
Chicago, however, quickly surrendered power-play scores to Jerome Iginla and Anton Babchuk only 3 minutes apart, allowing the Flames to tie the score with with less than 4 minutes remaining in the first frame.
Toews, however, scored 65 seconds later, poking his own rebound past Mikka Kiprusoff to put the Hawks up for good at 3-2.
Bolland added an empty-netter, Bryan Bickell also scored and Brent Seabrook chipped in with three assists in the victory, in which the Hawks' Patrick Kane left with an apparent leg injury.
Kiprusoff absorbed the loss after allowing three goals on 31 shots.