Havlat skated in on goal from the corner, shrugged off a stick to the shin and put a backhander past Miikka Kiprusoff to give the Wild a 2-1 lead 6:13 into the final frame.
Madden then scored a power-play marker less than 4 minutes later and Minnesota went on to beat the Flames for a second straight game after downing them in Calgary Saturday.
Havlat added an assist, Kyle Brodziak scored a first-period goal and Cal Clutterbuck added an empty-netter and an assist in the Wild win.
Niklas Backstrom was especially sharp in the first period when he turned aside 12 Flames shots en route to a 34-save performance.
Olli Jokinen scored and Kiprusoff allowed three goals on 22 shots for Calgary.
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