The Bruins chased goalie Brian Boucher by taking a 5-1 lead in the second period. New round, same problem for the Flyers. Philadelphia used two goalies in three of its seven first-round games against Buffalo.
For the second straight season, the Bruins lead the Flyers in the second round. The Bruins led 3-0 a year ago, then the Flyers became the third NHL team to rally with four straight victories to win a best-of-seven series.
Nathan Horton, Mark Recchi and Gregory Campbell also scored for Boston.
Game 2 is Monday in Philadelphia.
Since beating Montreal to advance to the second round, the Bruins had insisted they wouldn't be haunted by last year's epic collapse.
Perhaps it is fitting that Krejci was the Game 1 star.
Krejci watched Boston give away the series from the sidelines after he was knocked out of Game 3 a year ago with a dislocated right wrist. He needed surgery and missed the rest of the series.
He wasted no time in aiding Boston's quest to erase those bad memories, scoring a backhander off a rebound 1:52 in. The goal foreshadowed what was to come - Boston scored four of its five goals against Boucher on rebounds.
The Flyers did little to help Boucher, who won two games in relief vs. the Sabres, with lackluster play in front of the net. But Boucher failed to stop the often soft second chances.
He was yanked for rookie Sergei Bobrovsky late in the second period.
Tim Thomas, who saved 93 percent of his shots in the first round, was stout in net for the Bruins.
Danny Briere scored his seventh of the playoffs, and James van Riesmsdyk and Mike Richards added goals for the Flyers.
Briere tied it at 1-all, but Horton put the Bruins ahead for good with 36 seconds left in the first period. Boucher made the initial save on a shot to the gut, but Horton pounced and pounded the puck off Boucher's arm for a 2-1 lead.
Recchi didn't let the Flyers start yet another comeback with a quick goal 2:33 into the second. It was a soft rebounder that Boucher swiped at as it trickled behind him to the back of the net.
Krejci scored from the point and Marchand scored the fourth rebound goal with 2:46 left in the second for a 5-1 lead. That was all for Boucher.
Boucher, the Flyers' Game 7 winner, allowed five goals on 23 shots. Flyers coach Peter Laviolette again is forced to confront the weak link in the lineup. Bobrovsky won 28 games and started Games 1 and 2 against Buffalo. He was replaced by Boucher in Game 2 and never played again.
Richards, the Flyers captain, busted out of a scoring slump with his first goal of the postseason late in the third. His power-play goal made it 5-3.
Marchand quickly followed with his second goal for a 6-3 lead. Campbell completed the rout with 2:21 left.
Maybe the Flyers should have attempted more boarding, hooking, and high-sticking because even-strength play didn't help. Boston went 0 for 5 on the power play and extended their drought to 0 for 26 in the postseason. The Bruins went 0 for 21 against the Canadiens and became the first team to win a seven-game series without scoring a power-play goal.
Laviolette said the day before Game 1 he doesn't believe in momentum.
"I believe in desperation," he said.
The Flyers are desperate again.
Note: Boston won the season series 3-1. ... Laviolette was an assistant coach for the Bruins in 2000-01. ... The Flyers are 15-20 in a series when they lose Game 1.