WASHINGTON — If the Tampa Bay Lightning and their 41-year-old goalie, Dwayne Roloson, were exhausted, they sure hid it well.

Sean Bergenheim scored early, Steven Stamkos added the go-ahead goal on a power play, and Roloson made 26 saves, helping the Lightning beat Alex Ovechkin and the top-seeded Washington Capitals 4-2 on Friday night in Game 1 of the Eastern Conference semifinals.

“I don’t know about us being tired,” said Bergenheim, who scored 2:12 into the game. “I don’t feel it right now.”

Steve Downie had a goal and an assist, and Dominic Moore added an empty-netter with 40 seconds left for the fifth-seeded Lightning, who have won four straight games since falling behind Pittsburgh 3-1 in the first round.

Roloson got the shutout, and Bergenheim provided the only goal when Tampa Bay won at Pittsburgh 1-0 in Game 7 on Wednesday night. The Lightning flew straight to Washington that night, crawling into their hotel beds after 3 a.m. Thursday.

They were back on the ice for a 7 p.m. faceoff Friday.

“It was good for us, in a way,” Tampa Bay center Nate Thompson said. “We kind of get right back at it and don’t have a lot of time off. We’re still in game mode.”

That they were.

The Lightning’s get-ahead-and-focus-on-defense strategy confounded the Capitals.

Ovechkin was held without a point and limited to two shots, and Washington went zero for five on the power play — making Tampa Bay’s penalty killers 39 for 40 this postseason.

“They make it frustrating,” Capitals coach Bruce Boudreau said. “They just hang back, and you’re trying to push. They’re very good at it.”

Roloson only needed to make five saves in the third period.

“We’re surprised by the result tonight — but happy with it,” said the goalie, acquired from the New York Islanders on New Year’s Day. “We were lucky to win a hockey game. We had some bounces.”

Also on Friday:

Sharks 2

Red Wings 1

SAN JOSE, Calif. — Little-used Benn Ferriero scored 7:03 into overtime of his playoff debut on a deflected goal that gave San Jose a victory over Detroit in Game 1 of their Western Conference semifinal series.

Ferriero’s shot hit off Detroit defenseman Brad Stuart’s stick and got past Jimmy Howard for the game-winner just seconds after the Red Wings had killed off a four-minute penalty. Stuart slammed his stick to the ice in disgust after the goal, as the Red Wings again fell behind in their series to the Sharks.

Game 2 is Sunday in San Jose.