PHILADELPHIA -- Now in his 11th season, Philadelphia Flyers captain Claude Giroux is well aware that blowouts in the NHL do not occur very often, especially against a team such as the Washington Capitals, who allowed the fewest goals in the league last season.

"I don't remember the last time we won a game 8-2 and it's good to have a game like that," Giroux said after scoring two goals and assisting on two others in the Flyers' home-opening 8-2 dismantling of the Capitals on Saturday night at the Wells Fargo Center. "Tonight our shots were finding ways to go in and those games are more fun."

Forwards Sean Couturier and Scott Laughton also scored twice, Valtteri Filppula and Wayne Simmonds scored once, and Jakub Voracek and Shayne Gostisbehere each recorded three assists for the Flyers (3-2-0).

It was the Flyers' largest margin of victory over the Capitals since a 7-1 victory Dec. 20, 2008, in Philadelphia. It was also the first time the Capitals allowed eight goals in regulation since an 8-1 defeat in Pittsburgh on Jan. 25, 2006.

"We need to realize that we can't just give away the puck all the time," said Capitals center Nicklas Backstrom, who netted his third goal of the season. "If we don't realize that quick, it's going to be a long season. We have to manage the puck better."

Capitals coach Barry Trotz was even more pointed in his assessment.

"We were absolutely stupid with the puck," he said.

Goaltender Brian Elliott turned aside 21 shots to earn his third victory in his first season in Philadelphia.

Goaltender Philipp Grubauer (0-1-1) took the loss, allowing eight goals on 37 shots. Rookie left winger Jakub Vrana also goals for the Capitals (3-2-1), who have lost three of their last four games after opening the season with two wins.

The Capitals entered the game having taken at least one point from the Flyers in each of their previous eight meetings (5-0-3). But with veteran Matt Niskanen missing his first game with an upper-body injury, Washington played with two rookie defensemen -- Madison Bowey and Christian Djoos -- and it showed.

The Flyers, playing their first game following a 2-2-0 road trip, built a 2-1 lead on first-period goals by Couturier and Laughton. Laughton's goal was the Flyers' first short-handed score of the season and came after he intercepted a pass by Washington defenseman John Carlson.

Grubauer gambled by leaving his net and attempting a poke check, but Laughton held onto the puck and tucked it into an open net.

"That's the biggest point in the hockey game right there," Flyers coach Dave Hakstol said. "For us to be able to score a short-handed goal and turn that momentum back in our favor was a key moment. He made a good read and made a heck of a play to get in and finish it."

It was one of many setbacks for Grubauer, who received little help from his teammates.

Capitals forwards Alex Ovechkin and Evgeny Kuznetsov, who entered the game tied for the team lead with 10 points, each finished with a minus-4 rating.

"We know that's not going to happen very often," said Simmonds, who increased his team lead to five goals. "To me it doesn't matter if we win by six goals or one goal. We got the two points against a very good team."

NOTES: Capitals D Matt Niskanen was placed on long-term injured reserve after suffering an upper-body injury Friday night against the New Jersey Devils. Niskanen, who appeared to injure his left hand on a check into the boards, is not expected to need surgery but must miss at least 10 games or 24 days before returning to the lineup. With Niskanen sidelined, D Madison Bowey, 22, made his NHL debut for the Capitals. Bowey, taken 53rd overall in the 2013 draft, played on a third pairing with fellow rookie D Christian Djoos. Dmitry Orlov, Niskanen's normal defense partner, played alongside Aaron Ness. ... Flyers D Brandon Manning, a healthy scratch the previous three games, returned to the lineup on a third defense pairing with Radko Gudas. Manning replaced rookie D Travis Sanheim. ... The Capitals return home to face the Toronto Maple Leafs on Tuesday. ... The Flyers continue their five-game homestand Tuesday night against the Florida Panthers.