Anaheim outshot the Bruins 15-5 in the first period.
"I thought tonight we did start fast," Ducks coach Greg Cronin said. "We challenged them to come out and try and initiate the pace of the game. You want to try and create a difficult environment right from the beginning, I thought we were able to do that."
The Ducks made it 2-0 at 13:58 of the second period. Korpisalo made a save on Nikita Nesterenko's drive to the net, but the rebound went off the skate of Boston defenseman Michael Callahan and into his own net.
"A lot of disconnection and every goal started in the O-zone," Pastrnak said. "Lost the puck or unforced mistake, and then we are defending."
Pastrnak scored his 35th goal of the season with a one-timer from the right circle while on a 5-on-3 power play to cut it to 2-1 at 16:20. He is the fifth player in Bruins history to accomplish the feat in four consecutive campaigns, joining Phil Esposito (8 from 1967-75), Rick Middleton (6 from 1978-84), Peter McNab (6 from 1976-82), and Cam Neely (5 from 1986-91).
LaCombe made it 3-1 at 17:57 when he scooped the puck into the air from behind the net and it went off the arm of Bruins forward Pavel Zacha and into his own goal.