– Perhaps they’ve run out of gas or simply had their will broken by the Pittsburgh Penguins, but the San Jose Sharks look to be running on fumes.

Their personality as a freewheeling juggernaut has been absent for much of the Stanley Cup Final, and if they don’t rediscover it promptly, the Penguins will be celebrating their fourth Stanley Cup — and first won on home ice — Thursday night.

“We better, or we lose and we’re done,” said Sharks center Logan Couture, the NHL’s leading scorer in the playoffs with 26 points. “If you have a problem getting up for that game, you don’t belong in the sport.”

The Penguins have a 3-1 series lead, and they’ve done a masterful job in the first four games frustrating San Jose’s stars at every turn.

Joe Pavelski, who had a league-leading 13 goals in the first three rounds, is without a point in the first four games and is peeling himself off the ice constantly. The Penguins have swarmed the Sharks’ dangerous veteran, limited his time and space to the point he seemed to be pressing throughout Game 4.

Brent Burns hasn’t had a point since a two-assist Game 1. Joe Thornton has two assists but is scoreless in all three of San Jose’s losses. Patrick Marleau, too, has no points since scoring on a wraparound in Game 1.

It’s clear the Sharks are feeling the pressure, but they’re trying to simplify their thinking.

They were the NHL’s best road team in the regular season, and Couture said, “It’s just going and winning a game. Just go win three periods and move on. We’re going to battle to the end. Hopefully we can go to Pittsburgh, we’re confident we can go there and win a hockey game.”

The Sharks haven’t played with a lead all series long, and it’s putting a lot of pressure on coach Pete DeBoer to shorten the bench. That’s taken him out of the four-line rhythm that has long been DeBoer’s staple. In the past two games, he loaded up the top line with Pavelski, Couture and Thornton.

With young talent Tomas Hertl having missed the past two games and questionable for Game 5, DeBoer doesn’t have a lot of options waiting on the sideline.

“I don’t know if switching the lines up is the answer to getting the lead,” he said. “We’ve shortened the bench the last two games because we’ve been behind. It’s not ideal. Catches up to you, especially when you’re this deep into the playoffs and have played as many games as we have and logged as many miles as we have.

“There’s a saying that you dance with the girl you brought to the dance. I think that’s going to probably be our approach here going forward.”

The Penguins will do their best these next two days to ignore all the outside noise and hysteria in Pittsburgh as fans anticipate a second Stanley Cup in the Sidney Crosby/Evgeni Malkin era.

“Everyone is aware that [the Sharks are] going to be playing for their lives,” defenseman Ian Cole said. “I think if you’re not aware, you’re kind of a fool. If you say it’s just another game, it’s no big deal — as much as you want to say that, it’s not the case. It’s an elimination game in the Stanley Cup Final.”

Added veteran Matt Cullen, “We have a team that has a lot of guys that have been to the top of the mountain. We have a lot of guys that can share that experience and understand that experience.

“It’s nice when you have a group that has been there as opposed to one or two guys. We have a lot of guys that can help with that. Ultimately it just falls on all of us to come out with our best game. They’re going to push, and it’s a big game for them and a big game for us. We know it’s a huge opportunity.”