Boston’s Tyler Bertuzzi, left, moves in to congratulate David Pastrnak after he scored on Florida Panthers goaltender Alex Lyon in the first period Monday night in Boston. Winslow Townson/Associated Press

BOSTON — Brad Marchand scored his 50th career playoff goal, David Pastrnak and Jake DeBrusk also scored, and the NHL-best Boston Bruins opened the playoffs by beating the Florida Panthers 3-1 on Monday night.

Linus Ullmark, a Vezina Trophy candidate who led the league in wins (40), goals-against average (1.89) and save percentage (.938), stopped 31 shots and Tyler Bertuzzi added two assists for Boston, which controlled the game even with captain Patrice Bergeron sitting out because of illness.

Matthew Tkachuk scored for the Panthers and Alex Lyon made 26 saves but gave up Marchand’s goal on a relatively easy shot.

Game 2 is Wednesday night in Boston.

The Bruins captured the Presidents’ Trophy, setting NHL records in points (135) and wins (65). Florida, last season’s No. 1 seed, earned the Eastern Conference’s eighth and final playoff spot with a late-season push.

It’s the first playoff matchup between a No. 1 seed and the Presidents’ winner from the previous season since the award was introduced in 1985-86.

Pastrnak, a 61-goal scorer this season, was on the opposite side on the right wing from his usual spot on the power play. Bertuzzi collected the rebound of David Krejci’s shot in the slot and sent a quick backhand pass to Pastrnak, who snapped the puck into the net at 5:58 of the opening period.

Lyon gave up the soft goal early in the second when Marchand fired a seemingly harmless shot from the top of the left circle. Lyon bent down to catch it and it tipped off his glove, caroming into the net after hitting the inside of the right post.

Soon after, the TD Garden crowd started serenading him with chants of “Lyon! Lyon!”

Florida cut the lead in half when Boston defenseman Dmitry Orlov sent a blind, backhand pass directly out front, where Tkachuk collected it and flipped the puck past Ullmark at 6:34 of the second.

DeBrusk restored the two-goal lead when he dived into a pile and knocked the puck into the net out of a scramble near the crease late in the second.

As it did to so many opponents during its record-setting season, Boston bottled up Florida in the third.

NOTES: Bergeron left the regular-season finale in Montreal in the first period with an upper-body injury, then missed practice Saturday and Sunday. “We have not only Bergeron, but a couple of guys that have been under the weather,” Coach Jim Montgomery said after the morning skate. … Krejci missed the last six games of the regular season with a lower-body injury. … Bruins D Derek Forbort returned to the lineup. He hadn’t played since mid-March because of a lower-body injury. D Matt Grzelcyk was a healthy scratch.