The crowd booed Kessel during introductions and nearly every time he touched the puck.
"You hear it, but it didn't get to me," he said. "I've got to be better. You figure when you are dealt that's going to happen. It's part of the game."
His former teammates did quite well without his offensive skills that produced 36 goals last season, his third since being drafted by Boston with the fifth pick in 2006. They had extra motivation after one of their worst games of the season Friday night.
"It's a big win," said Savard, who had his eighth goal of the season and third hat trick of his career. "We got embarrassed the other night, so we kind of took it back here."
The Bruins, coming off a 5-1 loss to the Canadiens in Montreal, got an inspirational pregame speech from coach Claude Julien, then took control with two goals in the first 6:01.
"It would have been totally unacceptable for us to come out tonight and not be ready to play," Julien said. "One thing we had to do was to redeem ourselves."
Leading 7-0, Tuukka Rask lost a bid for his second shutout of the season when Niklas Hagman scored his team-leading 14th goal on a wrist shot from the bottom of the right circle with 4:14 left. Mikhail Grabovski added the final goal with 2:02 remaining.
The speedy Kessel had just two shots and committed a turnover on Boston's third goal, a slapshot by Zdeno Chara with 2:09 gone in the second period
"You've just got to be really aware when he's got the puck," Rask said. "There was one in the first period he shot on the power play, but, other than that, I think really we did a good job shutting him down."
The Bruins went ahead 7-0 with two goals in nine seconds midway through the third period. Johnny Boychuk, called up from Providence of the AHL on Saturday, got his first NHL goal. Savard then completed his hat trick one night after Mike Cammalleri scored a hat trick against Boston.
"You want to be one of the leaders here and that's what leaders do," Savard said. "They try and go out there and contribute."
The last Bruin to score three goals in a game was Kessel on April 12 against the New York Islanders.
"He didn't, obviously, have his best game, but we weren't very good around him," Toronto coach Ron Wilson said. "This game was over halfway through the second period. Unfortunately, we didn't do anything right."
The Bruins improved to 7-1-1 in their last eight games and ended the Maple Leafs' four-game road winning streak. Toronto is 4-2 in its last six games and 7-6-3 since Kessel returned, scoring 10 goals, after missing the first 12 games following shoulder surgery. The Maple Leafs were 1-7-4 without him.
Marco Sturm scored his ninth goal of the season at 5:28 of the first period when he deflected Derek Morris' shot from the right point past goalie Joey MacDonald. Just 33 seconds later, Savard made it 2-0 on a rebound after MacDonald stopped Chara's shot.
Any chance MacDonald had of stopping Chara in the second period was spoiled when the defenseman's shot from the left point deflected off a Toronto player and into the net after the puck slipped off Kessel's stick.
"It seemed like every shot they took hit a stick in front and found it's way," MacDonald said.
Just four days after signing a seven-year, $28 million contract extension, Savard scored his second goal with just over five minutes left in the second period. Michael Ryder skated behind the net and fed the puck to Savard, who poked it past MacDonald to make it 4-0. Mark Recchi got his fifth goal 6:36 into the third period.
Kessel, 22, became a restricted free agent after last season. He had 66 goals in three seasons but was traded on Sept. 18 for two first-round draft picks and a second-rounder. Boston general manager Peter Chiarelli said Kessel had told the Bruins he wanted to play elsewhere.
- Savard has four goals in his last three games.
- Rask entered the game with the second-best goals against average in the NHL and is 5-0-1 in his last six starts.
- Vesa Toskala replaced MacDonald at the start of the third period and allowed three goals.
- The Bruins next game is also at home against Toronto on Thursday.