Travis Dermott, Igor Ozhiganov and Zach Hyman also scored goals for the Maple Leafs, and Mitch Marner added three assists. Hyman clinched the game with an empty-net goal at 18:25 of the third, his fourth goal of the season.
Frederik Andersen made 38 stops in the Toronto goal.
David Pastrnak scored twice for Boston, with Torey Krug and Brad Marchand each notching two assists. Jaroslav Halak saved 27 shots for the Bruins.
Halak stopped Nazem Kadri on a breakaway at 12:01 of the first, and slightly more than a minute later, Boston's Colby Cave rang a shot off the Toronto goal post.
The Maple Leafs made it 1-0 at 17:44 of the first when Dermott scored from above the right circle on a pass from Mitch Marner.
Boston had a 10-9 advantage in shots on goal in the first period.
Pastrnak tied it for the Bruins on a power play at 3:39 of the second period. The right winger was parked near the left side of the net when Marchand whirled in from the right wing and backhanded a pass through the crease. Toronto's Par Lindholm had 16 seconds left in a hooking penalty.
Marner set up the first career NHL goal by Ozhiganov at 13:06 of the second, a shot from the left circle, just after the Bruins had exerted extreme power-play pressure during a too-many-men-on-the-ice penalty that had expired.
Pastrnak was unchecked in front of the net when he tied the game against at 14:22 with his 19th goal of the season.
Toronto regained the lead on a power play at 18:38 of the second when Leivo knocked in a rebound for his fourth goal of the season after Tyler Ennis was thwarted on his attempt. Boston's Anders Bjork was off for tripping.
Boston led 28-18 in shots on goal after two periods.
Toronto's Patrick Marleau, who had an assist, played in his 1,600th NHL game that was marked by a first-period video tribute.
--Field Level Media
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)