BOSTON -- Patrice Bergeron celebrated his first career hat trick twice.
So the fans who didn't throw their hats when Bergeron appeared to score in the second period -- the goal was later reassigned to Brad Marchand -- got another chance when Bergeron fired one that was undisputed and capped a night full of celebrations for Boston.
"Everyone is leaving the building with no hats on," Bergeron said. "I guess I wanted to get it because everyone threw their hats on the ice."
Tim Thomas stopped 31 shots for his sixth shutout of the season. Marchand and Tyler Seguin each had a goal and an assist and David Krejci added a pair of assists for the Bruins, who picked up right where they left off Monday night, when Boston rallied for four goals in the final 3 1/2 minutes of a 4-2 win at Pittsburgh.
After scoring five goals in a span of three games, the Bruins have 10 in their last two and will try to maintain that pace Thursday when they host Eastern Conference leader Philadelphia.
"I just think our forecheck's been a lot better and we're in sync as a line a little bit more," said Bergeron, who has 13 goals. "I thought we were doing good things also before but the puck wasn't going in and now it is, so obviously you have to take it and go with it."
The Bruins improved to 2-1 this season against the Senators. All three games have been shutouts, although not as one-sided as Tuesday. The Bruins finished with 39 shots, and all six goals came at even strength.
Five got past Brian Elliott, who faced 27 shots in two periods before being pulled. He had little chance of stopping most of them after blunders by the Senators' defense.
"When we had our chances we missed nets, we hit posts and we just had too many errors against a very good team that capitalized on their chances," Ottawa coach Cory Clouston said.
Marchand got his eighth goal of the season when he passed from the corner in front for Bergeron, who was tangled up with Sergei Gonchar. The puck deflected off the Ottawa defenseman's skate, giving Boston a 4-0 lead with 5:53 left in the second. Bergeron was initially credited with the goal and fans tossed hats to the ice, but the celebration was premature and the goal was reassigned to Marchand.
But more hats came early in the third, when Bergeron poked the puck away from Ottawa defenseman Chris Campoli to Marchand, who got it right back to Bergeron for a high wrist shot right past Mike Brodeur, who replaced Elliott at the beginning of the period.
Fans gave Bergeron a standing ovation when the Bruins announced it was his first career hat trick -- and there was no overturning this one.
"We didn't know if we had to give the hats back the first time," Bruins coach Claude Julien said. "It was nice to see. He had a really good game."
Bergeron, who gave Boston a 1-0 lead with an unassisted goal early in the first period, secured his third straight multipoint game with an unassisted goal early in the second on yet another blunder by the Senators' defense. Campoli couldn't hold in the puck at the blue line and Bergeron tapped it ahead to himself, then skated through another defender and corralled a high bounce before getting off a quick shot to put the Bruins up 3-0 with 17:10 left in the period.
Blake Wheeler also scored for Boston.
Boston's Mark Recchi played in his 1,613th game, moving past former Bruins great Ray Bourque for eighth place on the NHL's career list. ... Thomas and Bruins captain Zdeno Chara were selected as All-Stars on Tuesday. Ottawa defenseman Erik Karlsson was the Senators' lone representative.