Tanner Jeannot then pushed the lead to 3-0 at 10:06. After Jeannot stripped the puck from Vegas defenseman Ben Hutton on the forecheck, Sean Kuraly gathered it and fed Jeannot, who beat Schmid from the left circle with a high shot to the short side.
“It’s been really good,” Jeannot said of playing with linemates Kuraly and Mark Kastelic. “All three of us play a real simple game, support each other well and just want to be hard on other teams, play in the O-zone as much as we can, and we got rewarded.”
Pastrnak increased Boston’s lead to 4-0 at 7:25 of the second period. He took Nikita Zadorov’s backhand pass from the bottom of the right circle and scored to the short side with a quick wrist shot from the left hash marks.
Vegas cut the deficit to 4-1 on Eichel’s goal 31 seconds into the third, putting a rebound into an open net from the top of the crease.
“We need more urgency to our game,” Golden Knights defenseman Kaedan Korczak said. “Once the second started we got to our game, and it was much better. Just all around we need more urgency.”
Hertl’s power-play goal cut it to 4-2 at 3:01, and Dorofeyev made it 4-3 at 17:25 by scoring from a sharp angle with Schmid pulled for the extra attacker.
“We need to do a better job of putting out fires,” Vegas forward Reilly Smith said. “Collectively, as a group, we need to be better at not letting those momentum swings hurt us like that. … We don’t have to dwell on it too much because we have a game (at the Toronto Maple Leafs on Friday) and it’s worth the same amount of points as tonight, so we have to make sure we get off to a good start in the first period.”
NOTES: Boston scored its three fastest goals since Brian Rolston, Andy Hilbert and Rob Zamuner scored in a span of 52 seconds during a 5-0 win against the Montreal Canadiens on Dec. 20, 2001. … Defenseman Rasmus Andersson, who was acquired in a trade with the Calgary Flames on Sunday, has yet to play for the Golden Knights while he waits for his immigration process to be complete. He arrived at TD Garden during the first period, but Cassidy did not know after the game if Andersson would be available to play Friday in Toronto. “It’s all immigration related right now,” Cassidy said. “There’s no injury, no roster issue, so going to Canada I don’t know if that makes it easier or harder. He’s here, so that means there’s a chance, otherwise he wouldn’t have come.” … Eichel extended his point streak to 10 games (six goals, 12 assists).