The Bruins lost their third straight game, losing 10-2 Thursday night, and have been outscored 20-3 in the last three contests. They have allowed 28 goals in the last five games.
"We are embarrassed. It was almost like we gave up," Bruins defenseman Brad Stuart said. "We weren't mentally or emotionally prepared and you can't go much lower."
Toronto took advantage of Boston's defensive woes while handing the Bruins their worst loss of the season.
Alex Steen had a hat trick and two assists for the Maple Leafs.
With the Leafs trailing 2-1 after the first period, Toronto scored five goals in the second period.
"There has never been a doubt about his (Steen) talent," Maple Leafs coach Paul Maurice said. "There were questions to other parts of his game, but he has worked hard to improve those."
After Bates Battaglia and Steen had already scored to help Toronto regain the lead at 3-2, they each struck again along with Kris Newbury in a span of 42 seconds to give Toronto a 6-2 lead with 3:45 remaining in the period.
"We have to take advantage of the ice time we get with the guys out of the lineup," Battaglia said. "Everybody needs to contribute."
Steen began the night with 10 points for Toronto, which improved to 3-4-1 over the last eight and moved three points ahead of last-place Boston in the Northeast Division. It was the Maple Leafs second road victory since Nov. 24.
Matt Stajan scored two third period goals while Steen and Chad Kilger closed out the scoring for Toronto, which last scored 10 goals in 1998.
Battaglia tied the game at 2 when he knocked in the rebound of an Ian White shot beating Bruins goalie Tim Thomas at 1:36.
Steen put the Maple Leafs ahead 3-2 at 8:24 on a great individual effort when he drove toward the net and beat Thomas while falling to the ice.
John Pohl had a goal and two assists while Boyd Devereaux, Tomas Kaberle and White also chipped in with two assists.
After Pohl gave Toronto a 2-1 lead, Shean Donovan and Wayne Primeau responded with a pair of goals over the next 7:23 to put the Bruins ahead 2-1.
Toronto has outscored Boston 21-7 in its three victories while being outscored 12-4 by Boston in its four losses.
"We've lost our mojo," Bruins coach Dave Lewis said. "This is caused by a combination of breakdowns, but even in the dark days we have to stick together."
Thomas allowed eight goals for Boston and lost for only the second time in eight appearances against the Maple Leafs.
Raycroft had 29 saves for Toronto which beat the Bruins on Monday 5-1.
Notes: Darcy Tucker was out of the lineup for Toronto after returning last game. He was one of five forwards that missed the game for the Maple Leafs. ... The Maple Leafs scored five goals in a period for the second time this season. ... Toronto's record for fastest three goals is 39 seconds occurring on Jan 20, 1940.