Pacioretty and Mark Stone, who had two assists for Vegas, are tied for the NHL lead with 10 points.
The Sharks lost their third consecutive game and have been outscored 16-6 in that span. Martin Jones was pulled for the second time in three games after allowing two goals on seven shots. Aaron Dell made 17 saves in relief.
"When you look at the game, you can't put all of this on the goalies," San Jose coach Peter DeBoer said. "You have to score too. We have to find a way to solve Fleury. This isn't all on our goalies."
Game 5 is at San Jose on Thursday. Sharks center Joe Thornton can return after serving a one-game suspension for an illegal check to the head of Golden Knights forward Tomas Nosek in Game 3.
"You always want to win that next game," Pacioretty said. "You have to be prepared for whatever's brought at you. They're going to get a ton of energy from their crowd. They're going to play their best game of the series, and we have to be ready for that."
Despite the shutout, their third against the Sharks in 10 playoff games, the Golden Knights said they felt like they didn't play their best game. They were outshot 26-14 through the second period, including 18-7 in the first, but had a 13-2 advantage in the third.
"We still gave up almost 30 shots and we didn't catch them until the end," said Vegas forward Alex Tuch, who scored his first goal of the playoffs. "I thought we had a strong third period. It helps with more power plays and stuff, but we've got to be better. We've got to keep it going."
