Lazar scored into an empty net to make it 5-1 at 15:43, and Svechnikov cut it to 5-2 on the power play at 17:30.
The Hurricanes went 0-for-4 on the power play, all in the second period, including a 5-on-3 for 53 seconds when Boston did not allow a shot on goal. Jarvis and Nino Niederreiter each hit the crossbar on Carolina's first power play.
"You get a 5-on-3 there, and it's a big chance to obviously score a goal," Hurricanes forward Sebastian Aho said. "At the same time, we had some good looks with the two crossbars that almost brought us back. … It is what it is. We'll be better on the power play and 5-on-5 in the next game."
Bruins defenseman Hampus Lindholm had one shot on goal and two blocked shots in a game-high 24:38 of ice time after missing three games. He sustained an upper-body injury on a hit from Svechnikov in Game 2.
"It was great to be out there," Lindholm said. "Like I said this morning, watching hockey is not something I've ever been good at. So, super happy to be out there with the boys. It's going to be fun for us to go [to Carolina] as an underdog. … Looking forward to it."
NOTES:Marchand scored his 10th goal in games when the Bruins have faced elimination, passing Peter McNab for the most in their history. Marchand also scored his 49th NHL playoff goal, tying Patrice Bergeron for second in Boston history. They trail Cam Neely (55). … Swayman became the fifth Bruins rookie goalie to get a win when facing elimination and the first since Mike Moffat in Game 6 of the 1982 Adams Division Final against the Quebec Nordiques. The others are Don Simmons (Game 4, 1957 Stanley Cup Final against Montreal Canadiens), Frank Brimsek (Game 7, 1939 NHL Semifinals against New York Rangers) and Hal Winkler (Game 2, 1927 semifinals against Rangers). … Svechnikov had his third multigoal playoff game in the NHL. The only Hurricanes/Hartford Whalers players with more are Aho (four) and Kevin Dineen (four). … The home team has won each game in the series.