Belfour made 29 saves for his second shutout of the season and 60th of his career as the Toronto Maple Leafs stopped the Bruins' five-game unbeaten streak with a 2-0 victory.
Belfour is one shutout behind Patrick Roy for the lead among active goalies. The victory was the 378th of Belfour's career, breaking a tie with St. Louis' Tom Barrasso for second place on the active list.
"It's definitely a huge confidence builder for myself to hear the fans behind me 100 percent," said Belfour, who for the second straight home game heard chants of "Eddie, Eddie" at the Air Canada Centre.
"It's a big part of the game to know the fans are behind you. It just makes the team and myself play that much better."
Boston fired 21 shots over the final two periods. The Bruins' best scoring chance came midway through the second period when Joe Thornton eluded a check by rookie Ric Jackman in the corner, skated in front and got off a wide-open shot.
Belfour went to the ice and stacked the pads, then denied Thornton on his own rebound.
"I thought he made a few good saves tonight, but I don't think we had a lot of high-percentage shots," Boston center Brian Rolston said. "He's a good goalie. He's going to make the majority of those saves."
"He played a solid game, but we're a better offensive team than we showed tonight," added Bruins defenseman Bryan Berard, who played for the Maple Leafs from 1998-2000 before suffering a career-threatening eye injury.
Mikael Renberg gave the Maple Leafs a 1-0 lead 89 seconds into the final period with his sixth goal of the season. Tom Fitzgerald slipped a pass between two Bruins defensemen at the blue line and sent Renberg down the left wing.
Renberg fired a shot that hit goaltender Steve Shields on the right arm and slipped behind him into the net.
"I had a tough start and things are just coming around for me now," said Renberg, who has four goals in his last five games after netting two in his first 14. "When I shoot the puck, it seems to go in 'cause that was really not a good shot. I guess I'm lucky right now."
Renberg received a scare less than five minutes later when he collided with teammate Robert Svehla in front of the Toronto bench. Renberg crawled off the ice and the left with a left thigh injury but returned before the end of the period.
Paul Healey, recalled from St. John's of the American Hockey League before the game to fill in for the injured Alexander Mogilny, added a power-play goal at 4:46 of the third, doubling Toronto's lead.
Healey took a drop pass from defenseman Tomas Kaberle and snapped a wrist shot to the far post for his fourth NHL goal.
"It felt great tonight," Healey said. "It just felt really good for myself to see the puck go in."
It was the first defeat for the Bruins since a 2-1 overtime loss at Detroit on November 7. Boston had outscored opponents, 23-8, during its unbeaten streak.
"(The puck) just seemed to be bouncing over our sticks," Thornton said. "We just didn't get the bounces we've been getting the past 10 games."
Shields made 25 saves but suffered his first loss since October 31 against Anaheim.
Bruins center Jozef Stumpel left late in the second period with a left wrist injury and did not return. He is expected to be evaluated Wednesday in Boston.