Krejci, who had three goals in his previous 23 games, picked up a loose puck in front of goalie Martin Brodeur and scored his 16th of the season, triggering a cascade of hats onto the ice. Krejci had not scored more than one goal in a game this season.
Krejci was part of a new line with Seguin and Milan Lucic that produced all four goals. Boston blew a 2-0 lead, then fell behind 3-2 before Krejci tied it and won it.
Seguin also had an assist and Lucic added two assists in front of Tim Thomas, who contributed his first assist of the season.
The comeback allowed the Bruins to maintain a perfect record when ahead 2-0 or up by two goals at any time in a game. They are 12-0 when leading 2-0 and 29-0 when leading by two goals.
Bruins coach Claude Julien shook up his top two lines and the move paid immediate dividends, with two goals in the first 8:10 from the Krejci-Seguin-Lucic line.
More From ESPNNewYork.com
Rangers. Islanders. Devils. If you want hockey information, ESPNNewYork.com has you covered. Blog
Seguin picked off an errant pass in the Boston defensive zone, carried the puck down the right side and hit Krejci, who beat Brodeur 1:13 into the game.
Later in the period, Thomas made a pad save on Ilya Kovalchuk and the puck came out to Lucic. The big left wing carried it down the left side and found Seguin, who scored his first goal in 11 games and 21st of the season.
The Bruins dominated play for most of the period and took a 2-0 lead to the locker room. By the end of the second period they trailed and the home crowd was booing.
Bruins defenseman Joe Corvo made a bad pass at center ice that was intercepted by Kovalchuk, who came down on a two-on-one with Parise and fed the left wing for his 24th goal.
The Devils, shut out Monday night by the Rangers, tied the game after center Chris Kelly was tossed out of the faceoff circle and replaced by left wing Benoit Pouliot. Elias won the draw and went to the net. Petr Sykora appeared to tip Anton Volchenkov's shot and Elias was alone to tap in his 20th goal of the season, the ninth time he's reach that plateau.
A stunning goal by Clarkson at 17:46 gave New Jersey the lead. Left alone behind the net, the winger moved out and put the puck past Thomas from behind for his career-high 25th goal.
Krejci tied the game 5:30 into the third period.
D Greg Zanon, acquired from Minnesota at the trade deadline, made his Bruins debut. Fellow defenseman Mike Mottau, picked up from the Islanders on Monday, was scratched. ... Bruins defenseman Johnny Boychuk missed his second game with a concussion but skated at Thursday morning's optional practice and reported progress. "You want to take your time with these things," he said. "You've seen it before and how guys come back, they get hit and they're out for a longer period of time. We don't want that, especially being so close to the playoffs." . Devils defenseman Henrik Tallinder, slated to miss six to eight weeks with a blood clot in his leg, hit the six-week mark Thursday and told the Star-Ledger he won't be back in two weeks. . Clarkson and Devils center Dainius Zubrus received warnings but no fines or suspensions from the NHL for hits they delivered against the New York Rangers on Monday night.
Copyright by STATS LLC and The Associated Press
BOSTON, MA - MARCH 1: Mike Mottau #27 of the Boston Bruins poses for his headshot before the game against the New...