BOSTON — David Pastrnak's wide postgame grin had much less to do with the two goals he scored than the two points he helped Boston pick up with a 4-0 win over Tampa Bay.

The victory Tuesday night was all the Bruins needed to clinch their first playoff berth since 2014.

"It's a new feeling. I'm enjoying it a lot," said Pastrnak, who was still a few months out from being drafted the last time the Bruins played a post-season game. "I think every single guy in this room did his job today and that's why we got the win."

Drew Stafford and Zdeno Chara also scored for the Bruins, who extended their season-high winning streak to six games. More importantly, by winning in regulation, Boston guaranteed a return to the post-season after missing out the last two years.

"It's kind of a nice feeling to be in post-season again," Chara said. "This team battled through some ups and downs throughout the year and it was one of those years where we really had to come together."

Boston fans wary of another collapse in the final weeks celebrated by cheering throughout the final two minutes. After the final horn, the Bruins skated from the bench and swarmed goalie Tuukka Rask following his career-best eighth shutout of the season.

"It feels great. The city deserves it. The organization deserves it and we feel like we deserve it, too," said Rask, who stopped 28 shots. "Everybody can breathe a little bit easier now, but we still have two games left before the real games start."

The Bruins haven't lost since Tampa Bay's 6-3 victory in Boston on March 23.

The loss didn't knock the Lightning out of playoff contention, but Tampa Bay fell dangerously close with just three games remaining.

"Last time we came in here we beat them. Tonight they beat us," Lightning coach Jon Cooper said. "It's tough to hold that high standard of play for so long. We didn't have any margin for error and now our margin is razor thin."

Andrei Vasilevskiy kept Tampa Bay close with 34 saves.

Stafford was the first to beat him, backhanding in a rebound 5:56 into the second period. Pastrnak made it 2-0 on a one-timer with 3:54 left in the second and added another goal into an empty net with 1:02 remaining in the third off a pass from David Krejci, who had two assists.

It might have been a costly victory for the Bruins, who played the last two periods without leading scorer Brad Marchand after he speared Tampa Bay's Jake Dotchin in front of the Lightning net. Marchand received a five-minute major and game misconduct (on his bobblehead night), which could keep him off the ice longer once the NHL takes a look at the video.

Cooper said the extended power play in what was still a scoreless game actually seemed to set back the Lightning.

"We got nothing out of it. We weren't even really a threat," Cooper said. "You don't have to score on it, but you've got to turn the tide of the game and we didn't."

Marchand has been suspended six times in his career and was fined the maximum $10,000 by the league earlier this season for a questionable hit.

"It was an undisciplined penalty. There's no question about that," Marchand said. "It could have cost the team a very important game, but the guys did a great job of rallying and having a huge game."

NOTES: Boston C Patrice Bergeron went 17-0 on faceoffs. ... The Bruins improved to 18-7 since Bruce Cassidy took over as interim coach after Claude Julien was fired in February. ... Marchand has a career-high 39 goals and is trying to become Boston's first 40-goal scorer since Glen Murray had 44 in 2002-03. ... Lightning C Steven Stamkos (right knee surgery) missed his 62nd straight game, but said he could still return this week if the club needs him and he's ready. "As long as we're still in the mix, I consider it worth it," Stamkos said. ... Tampa Bay C Gabriel Dumont was not with the club after leaving to be with his pregnant wife. Dumont's absence combined with a string of injuries this season left Tampa Bay playing a man short Tuesday.

UP NEXT

Lightning: At the Toronto Maple Leafs on Thursday in the second of three straight on the road.

Bruins: Host the Ottawa Senators on Thursday in Boston's second-to-last game of the regular season.