BOSTON -- David Pastrnak scored his 40th goal of the season, and Pavel Zacha had two goals and an assist for the Boston Bruins in a 5-1 win against the Pittsburgh Penguins at TD Garden on Saturday.

Pastrnak gave the Bruins a 1-0 lead at 2:26 of the second period with a one-timer from the high slot. He is the fourth Bruins player to have four 40-goal seasons. The others are Phil Esposito (seven times), Rick Middleton (five) and Cam Neely (four).

“I won’t take it for granted, obviously,” Pastrnak said about the milestone. “It’s my job to score goals, but at the same time, you’re playing in the best league in the world, so I don’t take it for granted.”

Linus Ullmark made 38 saves for Boston (38-13-15), which is 4-1-1 in its past six games. Pastrnak, Brad Marchand, and Jake DeBrusk each had a goal and an assist, and Hampus Lindholm had two assists in his return after missing nine games due to a lower-body injury.

“I think since the Islander game in particular (a 5-1 loss to New York on March 2), where we laid an egg, I think we’ve come back with four really good games in a row,” Bruins coach Jim Montgomery said.

PIT@BOS: Pastrnak unloads a one-timer from the point to strike first

Kris Letang scored, and Alex Nedeljkovic made 18 saves for Pittsburgh (28-26-8), which has lost five of its past six games (1-5-0).

“There [were] parts of the game that we really liked,” Penguins coach Mike Sullivan said. “But like I said, there were other instances where I think we just shoot ourselves in the foot a little bit, which is a lack of awareness or diligence or whatever word you want to use to describe it. I just think we have to have a better understanding of game management.”

Zacha pushed the Bruins lead to 2-0 on the power play at 12:48 of the second, deflecting Morgan Geekie’s pass up and in from the right side of the net.

Marchand extended it to 3-0 at 18:25, taking Charlie Coyle’s pass into the middle and lifting the puck to the top right corner with his backhand.

“We feel good about our group,” Marchand said. “I mean, we have all year. We added two tough pieces, two great guys in the room [Pat Maroon and Andrew Peeke before Friday’s trade deadline]. … Love our group, feel very confident in it and come playoff time, anything can happen, and we have a group we believe in and that’s what’s important.”

Letang cut it to 3-1 at 2:51 of the third period with a slap shot from the left point, but DeBrusk made it 4-1 off a cross-ice pass from Marchand at 9:36.

“We had some looks pretty early and throughout the game,” said Pittsburgh forward Michael Bunting, who made his Penguins debut after arriving as part of the trade package from the Carolina Hurricanes in exchange for Jake Guentzel on Thursday.

“Obviously, they’re right there, and we want to be able to capitalize on those looks.”

Zacha forced the puck past Nedeljkovic at the net front at 15:33 of the third for the 5-1 final.

“It’s a lot of work to get [to the playoffs], but we’ve got to find a way to just go at it a game at a time at this point,” Penguins captain Sidney Crosby said. “You can’t grab all those points at once, and we’re playing some good teams, so we’ve got to be ready to compete and for that challenge and find a way here to get the next one and build off that.”

NOTES: Letang’s goal was the 164th, which surpassed Dan Boyle for 33rd all-time among NHL defensemen. … Pastrnak reached 40 goals in a season for the third year in a row. He has scored in two straight games after not scoring in the previous four. … Ullmark had lost each of his previous six starts before Saturday. … Zacha extended his point streak to four games (five goals, two assists).