BOSTON — The 2014-15 season has, at times, been a tumultuous one for the Bruins. But throughout the ups and the downs, there has generally been one constant.

Of course, given that Tuukka Rask is as hard on himself as anyone, he doesn’t see it quite that way.

“This year, I think it’s just funny,” he said following Boston’s 2-1 shootout win over Toronto on Saturday. “I’ve had my struggles too, but we’ve kind of been a Jekyll-and-Hyde team, and kind of up-and-down. So it’s been tough for us, but we’ve been battling, and hopefully it pays off at the end.”

Granted, Rask is right, to some degree. There was a brief period this season when he struggled slightly. From mid-November into early December, the goals against were up. The pucks getting past him seemed to be pucks he would have stopped nine times out of 10.

But that stretch didn’t last.

For the last three-plus months, as the Bruins have made their hardest and most strenuous push toward the postseason, Rask has been the best player on the ice nearly every night. He has routinely been the single most important factor that has kept his team in the game, night in and night out.

That was the case once again as the Bruins faced their fifth must-win game in a row, this time against the Maple Leafs in the regular season home finale. Toronto was looking to play spoiler, and the Bruins were looking to hold off the Leafs on a night when Detroit and Ottawa — the teams Boston is fighting against for a playoff spot — would emerge victorious.

In a word, the Bruins were desperate. They have been for the last several months. And once again, Rask held strong between the pipes in order to give his team a chance in a game it absolutely needed to win.

“When Tuukks is our best player, then you know we have a good chance at winning a hockey game,” said defenseman Torey Krug. “He’s seeing the puck right now, and it’s good. Guys are also committed to defense as well. It’s a combination of those two things, and we’re not going to give up many goals, and that’s what it takes to win hockey games right now.

“That’s how the Boston Bruins win hockey games: by not giving up more than a couple of goals.”

Following the pregame skate on Saturday morning, the Bruins weren’t shy about the fact that their game plan — now and always — is simple: Don’t give up more than a goal, two at the most. They aren’t a team that scores in droves. When they are forced to play a run-and-gun style of hockey, the result is generally unpleasant.

The Bruins have tightened up defensively over the last five or six games. That cannot be debated. But night in and night out, they have been able to depend on Rask to hold up his end of the bargain, too, and because of that, they have had the opportunity to win every single time they take the ice.

“That’s how we win, usually,” Rask said. “We don’t let in too many goals. … Overall, I think we’re tightening up. We’re taking away those second and third chances.

“I mean, first period, we played great, offensively, defensively, and then in the second period, we kind of got into their game, just trading chances and the rush game, which never works to our benefit. But overall, defensively, pretty good.”

Rask didn’t face as many shots as James Reimer on Saturday night — not nearly as many. But at times, that can make the goaltender’s job more difficult rather than easier.

“We had some really good chances,” Rask said. “In the first period, I’m looking at it — we gave [Reimer] a lot of shots that he saw, and then when you see those and it hits your stomach, it makes you feel good. I know that feeling, and it’s a great feeling — and then you kind of get into a rhythm, and it’s tough to score after that.

“I knew we were going to be in a dogfight after that first, but he made a ton of great saves, and he made it tough for us.”

But as Head Coach Claude Julien said after the game, sometimes, it’s not about how many shots you face. It’s about stopping the ones that count.

“Sometimes — and we say that a lot — it’s not the quantity, it’s the quality of shots,” Julien said.

He was referencing one in particular.

With about eight minutes remaining in a 1-1 game, a clearing attempt by Ryan Spooner didn’t make it out of the zone, and Rask was force to stack the pads and make two straight desperation saves to keep the score tied.

“That two-pad stack save at that one point was probably one of the biggest saves there, late in the third,” Julien said. “He had to make the saves when he needed to. Again, in that shootout, it’s the same thing — left on his own, and some pretty good shooters went up against him.”

Rask would finish with 27 saves on 28 shots through a shootout that lasted just three rounds, thanks to Patrice Bergeron. It could have been a frustrating night for Rask: His teammates peppered his counterpart with a whopping 50 shots and saw only a single one hit the back of the net. His frustration could have been compounded by the fact that the game advanced to the shootout, which has not been friendly to the Bruins this season.

But he stayed calm. No one would every deny that Rask is fiery, that he’s intense, that he’s unapologetically competitive, but he knows how to stay even-keeled when he has to be.

Saturday was one of those times.

“I can’t score any goals or anything,” Rask said. “So I just have to focus on keeping that puck away from our net, because it seemed like everybody was looking at the scoreboard, and then it makes us even tighter, you know? That’s what it looked like again today, so I tried to keep myself calm.”

There were times this season when people questioned Rask, especially coming off a Vezina Trophy-winning season during which he went 36-15-6 with a 2.04 goals-against average and a .930 save percentage.

But as it stands right now, there was never any reason to panic — not in mid-November, not in early December, not ever. During a season in which he has made a career-high 67 appearances in net, the third-most appearances in the league, Rask has been as good as ever.

For most, though, that was never really in question.

“Especially lately, the last week — you play against him, you watch him, he’s always making these highlight-reel saves, and you watch how hard he works — there’s no secret to why he’s so good,” said forward Brett Connolly. “He works hard, and very talented, and a guy who wants to win, and vey competitive. That’s why he’s so good, and for us, he’s going to have to continue being good.

“Obviously. he’s our backbone back there, so he’s been excellent.”