BOSTON -- The Boston Bruins power play went through a rollercoaster of events in Saturday night's 5-3 loss to the Tampa Bay Lightning that included a few positives and some downright ugliness.

Let's start with the good stuff.

The Bruins found the back of the net on a third-period power play when David Pastrnak scored his 48th goal of the season to help the B's trim the deficit to 4-3 with 13:23 remaining in regulation. The B's did just enough to screen Lightning goalie Andrei Vasilevskiy and make it tough for him to locate the puck in time to make a save.

Boston has now scored with the man advantage in four of the last five games, which is pretty good, and the totals over that span (four goals in 16 opportunities) are consistent with the team's season average (more on that below).

"Our top unit is one of the best in the NHL, if not the best," Bruins defenseman Charlie McAvoy said. "Everyone makes mistakes, it's a game. I certainly make mistakes, we all do. Tonight just -- stuff happens. It's a quick game. You go back and look at it and get better from it. We have so much faith in our power play, especially that top group. They always answer the bell. Nights like tonight happen, but there's so much skill, so much chemistry on that unit, they're huge for us."


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Despite Pastrnak's tally, there was still a lot to dislike from the Bruins power play in this defeat.

The Bruins had 7:04 of power-play time and generated just 11 shots attempts, five scoring chances and two high-danger scoring chances. This unit actually gave up more high-danger scoring chances (three) than it created. These quality scoring opportunities allowed the Lightning to tally two shorthanded goals 1:02 apart in the first period that put the B's in an early hole they couldn't climb out of. 

The Bruins failed to register a single shot on goal during their first power play five minutes into the game, but that wasn't even close to the worst part of this 2-minute man advantage.

Lightning forward Anthony Cirelli got the scoring started by winning possession off a defensive-zone faceoff and skating the length of the ice before beating Bruins goalie Tuukka Rask.

The Lightning quickly doubled their lead after a Torey Krug turnover set up defenseman Mikhail Sergachev's shorthanded tally.

It's not often you see a team give up two shorthanded goals in a game, much less on a single power play. In fact, the previous team to score a pair of shorthanded goals on one power play versus the Bruins was the Toronto Maple Leafs in an 8-3 win on Dec. 6, 1966. Bobby Orr was a rookie that season!

The Bruins power play actually has been a real strength most of the season. Boston has scored the third-most power play goals with 55, and it's 25.1 percent success rate with the man advantage trails only the Edmonton Oilers for the league lead. The top unit, headlined by the Pastrnak-Patrice Bergeron-Brad Marchand trio and Krug running the point is one of the most talented groups in the league.

A red-hot power play isn't required for playoff success -- just look at how the Bruins won the Stanley Cup in 2011 with an absolutely dreadful power play at times -- but it sure does help, especially when the physicality ramps up and referees give players a little more leeway on questionable calls. Being able to take advantage of your few power plays has the potential to swing a series.

The Bruins rank 15th in the league with 144 goals scored during 5-on-5 play. Five of the other seven Eastern Conference teams in a playoff spot are ahead of the B's in this category. This helps show how important the power play has been for the Bruins, whose 5-on-5 play has been good but not as dominant as we've seen in the past. 


There's no need to panic over the Bruins power play with a month left in the regular season -- it's still scoring goals at a pretty consistent rate -- but there are areas on this unit that need to be tightened up before the postseason arrives. 

WATCH: B's, Lightning engage in crazy line brawl to end 2nd period