“Just unfortunately we didn’t get the puck in there once or twice. We got caught too,” said coach Marco Sturm. “We didn’t do that for 40 minutes. Unfortunately, it happened in the third, those are the little details. I think that unfortunately it’s going to cost us a few points here. So that’s something we have to correct and try to get better at.”

Tampa Bay (48-22-6), which clinched its ninth straight playoff berth before the puck dropped thanks to the Rangers’ win over the Red Wings, got its first two goals from defensemen.

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Charle-Edouard D’Astous tied it early in the third, pushing his own rebound past Jeremy Swayman.

Darren Raddysh beat Swayman (20 saves) for the winner, sneaking one under the goalie’s right shoulder from a tough angle. It was Raddysh’s 21st goal, a Tampa season record for defensemen.

“I think in any 2-1 game, you’re going to get goals that are magnified,” said Swayman. “At the same time, it’s our job to move forward and really take positives, I think. A lot of great things came out of tonight’s game, so that’s what we need to focus on.”

With Swayman pulled, Nikita Kucherov scored his 42nd goal to ice it.

The Bruins went 0 for 4 on the power play, only showing life during the final opportunity in the third period.

“In the past, I think power play has given us an extra boost and we could have used it tonight,” said Sturm. “Unfortunately, we didn’t, but those guys need to step up, too. And that [elusive] second goal, it’s huge. And we had those opportunities and, unfortunately, we didn’t grab it.

“We played great. Again, we played a really, really good hockey game, five-on-five. We just got to [work on some] little details now.”

Space was at a premium over the first 20 minutes as both teams, predictably, played a tight checking style.

Casey Mittelstadt gave the Bruins a 1-0 lead with his 15th goal of the season.Mike Carlson/Getty

The Lightning avoided a potentially serious injury when Erik Cernak, one of their steadiest defensemen, took a skate to the face in the first period.

Fraser Minten picked off a pass just inside the Tampa blue line and raced down the slot. Cernak caught up and upended the Bruins rookie, whose skate went up as he went down and it caught Cernak.

After staying down momentarily, Cernak went to the bench and eventually to the room for minor repairs. He was back in a jiffy.

Lightning defenseman Darren Raddysh (43) prevented Charlie McAvoy from knocking home a rebound.Chris O’Meara/Associated Press

The Bruins had a great chance when Pavel Zacha’s rip trickled past Andrei Vasilevskiy. As a crashing Charlie McAvoy attempted to push it in, he was hooked down by Raddysh.

The game was interrupted for a clock malfunction — Raddysh was in the box for longer than the required two minutes because of the gaffe.

The Bruins were awarded another power play (Pontus Holmberg for holding Hampus Lindholm) but again, the man-advantage struggled, and it remained scoreless after one.

The Bruins dominated the first 15 minutes of the second period, getting good looks at — and chances on — Vasilevskiy. They cashed in when Viktor Arvidsson won a board battle after a Zacha keep-in, spun off his defender, and hit Mittelstadt in stride as the left wing barreled down the slot before snapping a quickie past Vasilevskiy’s blocker at 6:47.

“I thought it was a good shift overall,” said Mittelstadt. “I think we had them pretty hemmed in and then just kind of saw an opening and obviously a heck of a play by Arvy to get it to me and Pav to keep it in.”

Arvidsson has 10 points in six games and 25 in his last 23.

The Bruins nearly doubled the lead moments later when Sean Kuraly fed Tanner Jeannot at the goal mouth, but Vasilevskiy denied his former Tampa teammate.

Nikita Zadorov beat Vasilevskiy with an Artemis II-like rocket from the blue line, but it rang loudly off the post.

D’Astous was called for closing his hand on the puck and the Bruins power play finally looked connected, creating several chances only to be denied by Vasilevskiy.

The Lightning were buoyed by the kill and swarmed the Bruins end over the closing minutes.

Swayman’s best stops came on Oliver Bjorkstrand (shaft-of-the-stick save) and Nick Paul (sprawling glove save from his belly).

The Atlantic Division leaders carried it over to the third.

Jim McBride can be reached at james.mcbride@globe.com. Follow him @globejimmcbride.