BOSTON — Anders Bjork’s pass deflected off a defender’s rear end and Sean Kuraly’s leg to break a second-period tie and help the Boston Bruins win their fourth straight game, 4-1 over the Pittsburgh Penguins on Thursday night.

“It was an ugly one, so I didn’t even know if I wanted to take credit for it,” Bjork said. “You saw that ugly one go in, but our line was battling and that’s kind of what happens when you play the right way.”

Patrice Bergeron had two goals and Chris Wagner also scored for Boston. Jaroslav Halak stopped 16 shots for the Bruins’ second victory over Pittsburgh in three days. It was Bergeron’s fourth and fifth goals of the season and the first for Kuraly and Wagner.

“We knew the floodgates were going to open eventually,” Wagner said.

Cody Ceci scored his first and Tristan Jarry had 16 saves for the Penguins, who arrived in Boston with a four-game winning streak but have now lost two in a row.

“They’re fast, they’re hungry, they win every battle in the corner. We need to look into the mirror,” Penguins forward Evgeni Malkin said. “It’s not a pretty game right now. We need to play simple and just work, work, work.”

Wagner gave the Bruins the lead early in the first, but Ceci tied it for the Penguins with five minutes left in the period. With about a minute to go in the first, Bjork made a nice move to get past a stickless defender at the point, then flipped the puck toward the net.

It bounced off of Teddy Blueger’s bottom, through another defender’s legs before deflecting Kuraly’s leg into the net.

Bergeron made it 3-1 in the second, getting the rebound after his first attempt hit a skate and sliding the puck over to his backhand then past Jarry. The Bruins captain added another on the power play early in the third.