Tuukka Rask made 26 saves for Boston (48-17-11), which passed the Lightning and leads them by one point with one game in hand. The Bruins, who lead the Eastern Conference, are 4-0-3 in their past seven games.
"I guess when you look at the importance of the game, they've been in first place pretty much as long as I can remember this year. So that's nice, to pass them," Bruins coach Bruce Cassidy said.
WATCH: [All Lightning vs. Bruins highlights]
Andrei Vasilevskiy made 26 saves for Tampa Bay (51-22-4), which has lost three in a row for the second time this season. The Lightning led the division since Oct. 19.
"I thought we played great in the second and third. I thought we were the better team, whether it was them sitting back on a two-goal lead or us pressuring, I thought we controlled the play," Lightning captain Steven Stamkos said. "It's tough ... against a team like that to go down two and expect to win, they defend so well. Obviously we'd like to be on the other end of it."