After 60 scoreless minutes, Brad Marchand needed just seconds to lift Boston to the win.
Marchand scored 10 seconds into overtime, Jonas Gustavsson made 42 saves and the Bruins beat the Tampa Bay Lightning 1-0 on Tuesday night in a matchup of Atlantic Division leaders.
Patrice Bergeron sent a pass from the right wing through the slot that Marchand redirected past Ben Bishop for his 34th goal.
"It was big," Marchand said. "We're battling for position. We're definitely happy with the outcome. It's showing we're learning how to win these games."
Boston and Tampa Bay both have 83 points but the Bruins have played one more game.
Bishop stopped 32 shots. Gustavsson, subbing for starter Tuukka Rask, improved to 11-5-1 this season with his seventh career shutout.
"That was a good hockey game," Tampa Bay coach Jon Cooper said. "It was up and down, bodies flying all over the place. Both goalies played extremely well."
The Lightning had the first nine shots during the opening seven minutes of the third period, including Nikita Kucherov's that required a nice glove save by Gustavsson.
"He was outstanding," Bruins coach Claude Julien said. "That's a huge boost for our team when you can put a goaltender in a big game like that and play the way he did."
Bishop stopped Loui Eriksson's shot from just outside the crease with 3 minutes to go in regulation.
Tampa Bay outshot Boston 27-22 through two periods and 42-32 through 60 minutes.
Marchand had his short-handed breakaway backhander gloved by Bishop with 3 minutes left in the first.
During the same Tampa Bay power play, Kucherov was hit in the head by the elbow of Boston's John-Michael Liles and went to the locker room. There was no penalty called on the play.
Kucherov returned for the start of the second period.
"I was trying to step into him as he went by me ... I didn't think I came up high with it," Liles said. "I don't know if he was falling or if he ducked. I didn't see a replay on it, so I'm not really sure. I'm not trying to hit him up high."
Gustavsson extended his left leg to stop an in-close redirection by Alex Killorn midway through the second.
"He was perfect," Tampa Bay center Brian Boyle said. "It's tough to beat that."
Tampa Bay hit the post twice, and Bishop turned aside a point-blank chance from Eriksson late in the second.
The Lightning had all four of the power plays.
NOTES: Marchand (six) and Eriksson (five) combined for 11 shots. ... Marchand has six career overtime goals. ... The Lightning were without D Anton Stralman, who sat out due to illness. D Braydon Coburn missed his second straight game with a lower-body injury. ... Gustavsson is 6-0-4 against the Lightning. ... Tampa Bay D Luke Witkowski was recalled from Syracuse of the AHL and reassigned back to the minor league team after being scratched. ... The Bruins had a streak of scoring a first-period goal end at nine straight games.