"Obviously, ideally we don't want to put ourselves in the situations where we've got to come back like that," said Boston goalie Tim Thomas, who made a season-high 42 saves while extending a franchise record by winning his eighth consecutive decision to start a season.
"But if we're in [that situation] we know we're not out of it."
The Bruins improved to 6-1 on the road. They had lost their previous two after winning seven of eight.
Playing without top center David Krejci due to a concussion sustained in the team's previous game, fifteen of Boston's 18 skaters had at least a point.
"I think for the third period, for sure, and for parts of the rest of the game, the guys really kind of came together and tried to do it by committee," Thornton said. "Every line chipped in, and you're going to need that when you're missing a guy like Krejci."
Sidney Crosby had a goal and two assists for the Penguins, who have lost six of their past eight and fell to 2-5 at the new Consol Energy Center.
Pittsburgh took a two-goal lead after Chris Kunitz and Crosby scored over the final 4:16 of the second period. Crosby moved into a tie for second on the NHL goal list when he was credited with his 10th on what was intended to be a pass across the slot but deflected off of Bruins defenseman Mark Stuart and past Thomas during the final minute of the second to make it 4-2 Penguins.
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"We said in the locker room [during the second intermission], 'We still have an opportunity to win this game," Wheeler said. "It speaks to what we have in the room that guys know it's never over until it's over. It certainly helps to get one early because it gives you some confidence, and we took it from there."
Horton scored his seventh of the season 3:49 into the period on a turnaround wrist shot from low in the left-wing circle. Chara's seventh was a one-timed shot from the slot while on a 3-on-2.
"I think just the way we came out on the ice [for the third] is unacceptable," Kris Letang said.
Thornton had his second in three games when he collected a puck at his own blue line, carried it down the right wing and beat Pittsburgh goalie Brent Johnson high to the glove side.
"We made big mistakes [in the third]; that basically was what it was," Crosby said. "It's not like we gave them a ton of chances, but the ones we did were big ones, and they capitalized on them all. We got into playing some pretty risky hockey, and we paid for it."
Asham's goal 1:05 into the game was his first as a Penguin, and Orpik's was his first of the season and ninth of his 459-game career.
The 42-year-old Recchi, who began his career in Pittsburgh 22 years ago, scored his the first goal of the season and 564th of his career.
There were two fights in the first 7 minutes of the game and a third midway through the second period. None, however, involved Matt Cooke. Last March 7, the Penguins' agitator knocked Bruins gifted center Marc Savard out of the game -- and the remainder of his regular season -- with a blind-side hit to the head.
Although Savard returned during the playoffs, he has not played yet this season due to post-concussion symptoms. The Bruins vowed a measure of revenge, but other than Thornton fighting Cooke 2 minutes into the only meeting between the two teams since then (11 days after the hit), there has been no visible on-ice retribution.
Recchi's power-play goal was the first the Penguins had allowed in five games. ... Before allowing two Wednesday, the Bruins had allowed only four first-period goals during their first 11 games this season.
Copyright by STATS LLC and The Associated Press
Arena: CONSOL Energy Center Location: Pittsburgh, Pennsylvania
Referees: Kevin Pollock, Ian Walsh Linesmen: Michel Cormier, Derek Amell
Attendance: 18,113 (100.1% full)
Team Stat Comparison
Power Play Goals
Power Play Opportunities
Shots on Goal
Arron Asham (1)
Assists: Evgeni Malkin, Matt Cooke
Mark Recchi (1)
(Power Play) Assists: Tyler Seguin, Patrice Bergeron