"It was a big goal," said Sharks forward Logan Couture, who had two assists. "At the start of the game, they actually had some better looks than we did. I think they came out hard and better than we did, and then Marcus scored, and Joonas' goal was big as well. The 2-0 goal was a massive goal heading into the first intermission."
Donskoi, who returned to the top line after missing Game 3 with a lower-body injury, went end to end and beat Fleury with a snap shot from the high slot with six seconds left in the period. He skated along the left boards, cut toward the middle, and shot the puck between defenseman Brayden McNabb's legs and over Fleury's glove.
"They came with speed and cut across the middle and shoot between the D's legs," Fleury said. "I just didn't pick it up, and when I saw it, it was too late."
Hertl increased San Jose's lead to 3-0 at 5:35 of the second period when he knocked in a rebound from close range after Fleury stopped Mikkel Boedker's wraparound.
"I just tried to crash the net, and [Boedker] made a great play," Hertl said. "I got an empty net and I put it in. I should have scored a couple more."
Pavelski scored a power-play goal at 11:43 of the third period to make it 4-0.
"I think our group's done a great job all season long of dealing with adversity and injuries and everything like that," Vegas defenseman Deryk Engelland said. "It's a tough one to lose today, and I think our guys will be ready to go next game.
"Going into the series you knew they were going to be a fast, relentless team, and I don't think it surprised anyone."