Boston finished with 112 points, one behind the division and conference champion Tampa Bay Lightning. The Bruins needed a win to claim their first division crown since the 2013-14 season and their 26th overall.
The Bruins will face the Toronto Maple Leafs in the first round of the playoffs. That series begins Thursday in Boston.
The Sunday contest -- the last game of the NHL regular season -- was the makeup of a game that was postponed Jan. 4 due to a blizzard.
Henrik Borgstrom scored his first NHL goal and Evgenii Dadonov (28th of season), Frank Vatrano (seventh) and Maxim Mamin (third) also scored for Florida, which finished just outside the playoff picture in third place in the Eastern Conference wild-card hunt.
James Reimer finished with 33 saves for the Panthers, who were eliminated from playoff contention Saturday after a Philadelphia victory. Reimer left the game with an apparent injury with 8:07 remaining and was replaced by backup Roberto Luongo, stopped all eight shots he faced.
David Pastrnak scored his team-leading and career-high 35th goal, David Backes scored his 14th and Tuukka Rask made 22 saves for Boston, which finished the regular-season slate with four losses in its last five games.
Boston's Rick Nash (concussion), Sean Kuraly (upper body) and Riley Nash (ear laceration) all missed the game, although all three are progressing and Riley Nash will resume skating on Monday.
Aleksander Barkov (upper body) sat for Florida.
Borgstrom quieted an excited TD Garden crowd with his goal 1:22 into the first period. Backes pulled the Bruins even with a goal at 8:18 of the first, only for Vatrano to strike at 16:46 of the opening period to restore the Panthers' lead.
Mamin's tally at 13:33 was the only goal of the middle period.
Pastrnak gave the Bruins life with his power-play goal at 9:54 of the third. Dadonov put the game out of reach with 1:49 to play.
Before the game, the Bruins honored longtime national anthem singer Rene Rancourt ahead of his final regular-season performance.
Rancourt, a 78-year-old native of Maine, has been performing the anthems at Bruins games for 42 years and is retiring after this season.
--Field Level Media
Florida | Boston | |
Frank Vatrano 2 | Points | David Backes 1 |
Frank Vatrano 1 | Goals | David Backes 1 |
Jared McCann 2 | Assists | Patrice Bergeron 1 |
N/A | Power Play Goals | David Pastrnak 1 |
N/A | Short Handed Goals | N/A |
Roberto Luongo 1.000 | Save Percentage | Tuukka Rask .846 |
James Reimer 33 | Saves | Tuukka Rask 22 |
Team | Shots | Goals | Power Play | Penalty Kill | Penalty Mins | Face Offs Won |
Florida | 26 | 4 | 0-3 | 3-4 | 8 | 23 |
Boston | 43 | 2 | 1-4 | 3-3 | 6 | 35 |