Bergeron scored 47 seconds into the extra period to give the Bruins a 2-1 win over the Buffalo Sabres.
The Bruins won their second straight game, only the second time this season they've produced a winning streak. This one moved Boston within two points of first-place Buffalo in the Northeast Division.
"It's always disappointing losing ground," Buffalo coach Lindy Ruff said. "They've been playing real well and getting some healthy bodies back. They're playing a lot better."
"That's not really a set play," said Bergeron, who last scored in overtime on Nov. 16, 2006 against Toronto. "You win the faceoff and go to the net. Especially in a 4-on-4, there's more room."
Chara's drive made it all possible.
"So much depends on controlling the puck and controlling the play," the big defenseman said. "I tried to find a lane and wrist it to the net. It's a really innocent, simple play, but those make a big difference."
Buffalo outshot Boston 15-6 in the third period and had several good chances to take a lead against goalie Tuukka Rask, who made his third straight start.
Rask stopped 25 shots, including a point-blank save on Thomas Vanek three minutes into the third, and a blocker stop on Jochen Hecht's snap shot from the left circle with about four minutes remaining.
"Every game, [Rask] has gotten better and better," Boston coach Claude Julien said. "We're in real good shape there, when you've got a young goalie like him coming up big for us."
Miller made 24 saves, including 14 in the second period.
Gaustad opened the scoring 4:20 into the first period, parking himself in the slot and tipping in Jason Pominville's shot from the blue line.
It just wasn't enough offense.
"We got as many shots as we could," Gaustad said. "Some of them didn't go in."
Lucic converted a 2-on-1, give-and-go with Byron Bitz midway through the second period to tie the game. Bitz delivered a perfect cross-ice pass to Lucic, who was charging in from the left.
"I'm relieved. It took a little longer than I hoped [to score the first goal]," Lucic said. "We can't be satisfied with what we've done these last few games. We have to keep pushing forward and wanting it more."
Buffalo played most of the game without Drew Stafford, who is tied for the team lead with six goals. He skated off gingerly midway through the first period and didn't return. Ruff described Stafford's injury as a lower body bone bruise, and said the winger would miss Saturday's game at Ottawa.
- Buffalo and Boston have played only four games apiece against Northeast Division opponents.
- The Sabres had won four straight at home against the Bruins.
- Buffalo D Toni Lydman played in his first game since Oct. 21.
- Rask's starting streak is the longest of his 13-game NHL career.
- Boston is halfway through its four-game road trip, which continues with games at St. Louis and Minnesota on Monday and Wednesday.