Pastrnak pulled even with Brad Marchand for the Bruins' team lead in goals. Danton Heinen (16th goal), David Backes (13), Noel Acciari (10) and Tommy Wingels (nine) also lit the lamp as Boston ended its first three-game skid since mid-November.

With Tampa Bay losing 3-2 in overtime at Carolina on Saturday, the Bruins (112 points) pulled within one point of the Lightning for first place in the Atlantic Division and Eastern Conference.

Boston would win the division and conference with any type of victory in Sunday's regular-season finale against Florida.

Ryan Dzingel (23) scored two goals and Danny Taylor had 30 saves for the Senators, who ended their season with 10 losses in their final 12 games.

Ottawa missed the playoffs for the third time in five years. Last season, the Senators beat Boston in the first round of the playoffs and advanced to the Eastern Conference Finals before losing to eventual champion Pittsburgh in seven games.

Anton Khudobin made 26 saves to bolster the Bruins.

Dzingel opened the scoring for Ottawa with his first goal 12:31 into the opening period.

After being in a 1-0 hole through 20 minutes, the Bruins answered with a big second period as goals from Pastrnak (at 8:08), Wingels (8:59) and Heinen (17:01) had the hosts up 3-1 going into the third.

Dzingel's second tally at 7:07 of the final period gave the Senators life until Acciari salted the game away with a goal at the 18:09 mark. Backes added an empty-netter at 19:17 to cap the scoring.

Boston received encouraging news before puck drop as Rick Nash skated on Saturday morning after revealing he has been dealing with a concussion. Nash hasn't played since the March 17 game at Tampa Bay.

--Field Level Media