Tim Thomas had 23 saves for the Bruins, who won for the fifth time in six games. The Maple Leafs lost their sixth straight. Primeau scored the game-winning goal with 5:53 remaining when he knocked the rebound of a shot by Mark Mowers past Maple Leafs goalie Jean-Sebastien Aubin. Patrice Bergeron added an insurance goal with 1:19 left for Boston.
Toronto dropped its fourth straight to Boston and scored only one goal against the Bruins for the fourth straight game. The teams were playing for the fifth time in 28 days.
The Maple Leafs' struggles in the third period continued; the team has been outscored 17-2 during their losing streak and has blown a pair of two-goal leads in the final period the previous two games.
Stuart got Boston even at 1-1 with 9:47 remaining when his wrist shot beat Aubin over the right shoulder.
Jeff O'Neill scored the lone goal for the Maple Leafs. His slap shot caromed off the boards into the goal crease and he then tipped the puck into an open net while Thomas was out of position at the 5:04 mark of the second period.
Aubin hasn't won since Nov. 5 and has beaten the Bruins once in nine tries.
Stuart has five points in the last three games including two third-period goals in Boston's victory against Montreal on Monday.
Shean Donovan added two assists for Boston, which has yet to be shutout this season.
Notes: Tomas Kaberle has no goals in 11 games despite being second on Toronto on points. . . . Thomas made his 20th consecutive start. . . . P.J. Axelsson missed his third straight game with a foot injury. . . . Despite winning records, both Boston and Toronto have been outscored this season at even strength. . . . Thomas has never lost to the Leafs in regulation.