The Bruins owned Thursday’s first period. They compiled chances that goalies other than Henrik Lundqvist might have been plucking out of their nets. They didn’t play poorly in the second. Neither team had scored.

Yet Bruce Cassidy was thinking about changing his lines. 

The sun has been shining on Cassidy. The Bruins are 7-2-0 under Cassidy, even after the 2-1 loss to the Rangers. 

Sunshine, however, is not blinding Cassidy to the reality of the situation: The Bruins are still in a dogfight. 

 The first-place Canadiens stretched their lead over the third-place Bruins to eight points with a 2-1 win over Nashville. Ottawa is two points north of the Bruins after a 2-1 victory over Colorado. The Bruins are three points clear of Toronto, which holds the No. 2 wild card. 

 “The takeaway is that we lost,’’ Cassidy said. “At this time of year, we need points. That’s the big picture.’’ 

It is not good enough for the Bruins to shake their shoulders, say they had tough puck luck, and say they were the better team despite the loss, even though that’s all true. 

Points are points. The Bruins recorded none on a night when they should have gained at least one. 

 So for Cassidy, who was already pondering a shuffle when the game was scoreless, being down by two in the third period was a good time to shake up his lines. David Pastrnak, the No. 2 right wing, moved up to the first line. Frank Vatrano, the No. 3 left wing, moved up to David Krejci’s right flank. Matt Beleskey, Ryan Spooner, and David Backes formed the third line. 

“I thought about it earlier, but you’re in a 0-0 game and you don’t want to out-think yourself either,’’ Cassidy said.

“You want to give guys and certain lines a chance to play through and generate. I thought we got some chances with the lines. We just didn’t finish. Then when they got the lead, well, good a time as any. We’ve moved Pasta in there at certain points. We know it can be a very dynamic offensive line. If we put it together tomorrow, it would be a great line for good. But we’ve tried to balance the scoring. It’s worked out for the most part. It just didn’t happen tonight in terms of finish.’’ 

 The changes produced the Bruins’ only goal. Pastrnak attacked Nick Holden one-on-one, drew a delayed call, and flung a one-handed backhander on net. Marchand was stationed at the right post to guide the puck over the line before Lundqvist could stop it with his glove. Pastrnak and Marchand are no strangers to connecting for goals. 

“He’s obviously a very skilled player,’’ Marchand said. “He’s playing incredible this year. You see him out there, he creates a lot from nothing. It’s good sometimes to throw a different look at them. Even after that, Backs had a really good opportunity on another line. We were getting opportunities all night long. We easily could have had a couple goals throughout the lineup. If we continue to play this way, we’re going to be good.’’ 

The disappointing thing about the one-goal loss is how two players performed considering the situation: Jimmy Hayes and Beleskey. 

A day earlier, management put the fast friends on notice by acquiring Drew Stafford from Winnipeg for a conditional sixth-round pick. The Bruins landed the right-shot wing to provide scoring depth and veteran presence on the bottom two lines. Hayes and Beleskey are most at risk of losing their ice time to Stafford, even though the ex-Jet (four goals in 40 games) has struggled to put pucks in net. 

 Against the Rangers, Hayes and Beleskey could take solace in their combined output: zero shots on net. Hayes played a game-low 8:04. Beleskey earned just three more seconds than Hayes. As a right wing, Hayes could be the first to sit in Stafford’s place. 

But even playing his off wing, Stafford might bring more heat than Beleskey. The ex-Duck has a history of playing well when he’s hard on pucks and even harder on opponents. But Beleskey has been so far removed from the play that he hasn’t applied his physicality in critical situations. 

Stafford arrived in Boston on Thursday after a layover in Minneapolis, where he briefly met wife Hali, who is 33 weeks pregnant with twins and living in Minnesota. Stafford will practice with his new teammates Friday. He is a good bet to play Saturday against the Devils, perhaps in Hayes’s spot while Tim Schaller, scratched against the Rangers, reclaims his fourth-line position from Beleskey. 

This has not been a memorable season for Stafford. Last year, the ex-Sabre scored 21 goals in 78 games. This season, injuries and the emergence of Patrik Laine and Nikolaj Ehlers made Stafford an afterthought in Winnipeg. Given his expiring contract and the Jets’ likelihood of missing the playoffs, Stafford knew a deal was coming. 

“I was realistic with the contract situation and the way things were going,’’ Stafford said. “Fortunate enough to be in a situation where the type of relationship you have with your general manager, Kevin Cheveldayoff, and my agent, it was very up front with things.’’ 

 Stafford is desperate to prove his new employer right. Right now, desperation is not just a good thing. It’s required.  

Fluto Shinzawa can be reached at fshinzawa@globe.com. Follow him on Twitter @GlobeFluto.