Grabovski worked a give-and-go play with John-Michael Liles and snapped a wrist shot into the net after spinning around in front of Canadiens goaltender Carey Price, handing the Leafs their fifth win in seven games to start the season.
James Reimer stopped 9-of-10 shots before being knocked out of the game after a first-period collision with Montreal's Brian Gionta. Jonas Gustavsson earned the victory by turning aside 15-of-18 shots the rest of the way.
Travis Moen scored twice and Price made 22 saves for the Habs, who fell to 0-3-1 at home.
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