Tampa Bay also lost captain Vincent Lecavalier, who broke his right hand and will be sidelined up to four weeks.

With the score tied at 2, Semin converted on a power play with 15:27 left, knuckling a shot from between the circles past Lightning goalie Dan Ellis. With 9:14 remaining, Semin one-timed a pass from Backstrom for his team-high 11th goal and a two-goal lead.

Semin added an empty-net goal with 16 seconds remaining.

Tom Poti and Mike Knuble also scored for Washington.

Steven Stamkos, the NHL’s scoring leader, had a goal and an assist for the Lightning. Teddy Purcell and Ryan Malone also scored for Tampa Bay, which has lost three of four.

Purcell’s goal midway through the first period gave Tampa Bay a 1-0 lead. Purcell skated to the left of the goal when be batted Sean Bergenheim’s rebound out of midair and past Michal Neuvirth.

Poti, returning to the Washington lineup after missing eight games with a groin injury, tied it 2:21 into the second period. Left uncovered along the right wing, Poti used a backhand shot to sweep Semin’s rebound by Ellis for his first goal of the season.

At 7:51, Knuble put the Capitals ahead with a goal from behind the goal line. When Brook Laich’s shot skittered wide right, Knuble collected the loose puck and tucked it inside the right post.

Tampa Bay tied the game early in the third period after Washington’s John Erskine went off for boarding. Malone was at the right post to knock in the rebound of Martin St. Louis’s drive from just inside the blue line at 2:43, the Lightning’s first power-play goal in five tries.

Lecavalier, who has three goals and six assists in 10 games, was hurt early in the first. He retreated to the bench and then to the dressing room, but came back to play.

He didn’t come out of the game until after the second period, when he skated nine shifts. Lightning coach Guy Boucher said Lecavalier played until he could no longer grip his stick.

The break occurred in the upper portion of the hand, near the knuckle of the index finger.

Flyers 8, Hurricanes 1 — Jeff Carter had his second career hat trick as Philadelphia won in Raleigh, N.C.

Danny Briere scored two goals, Scott Hartnell had a goal and an assist, and Nikolay Zherdev and Mike Richards also scored for the Atlantic Division-leading Flyers.

Sergei Bobrovsky stopped 35 shots for Philadelphia.

Thrashers 5, Wild 1 — Ondrej Pavelec won for the first time since collapsing early in the season opener, making 32 saves in host Atlanta’s victory over Minnesota.

Pavelec collapsed two minutes into the Thrashers’ opener Oct. 8 against Washington and sustained a concussion when the back of his head hit the ice.

Rangers 3, Sabres 2 — Artem Anisimov scored his second goal of the game 1:32 into overtime to lift New York over visiting Buffalo.

Anisimov forced a turnover in the Buffalo zone and eventually found a loose puck in the slot for a shot past Jhonas Enroth.

Ruslan Fedotenko had a goal and assist, and Martin Biron made 29 saves as a late replacement for Henrik Lundqvist, who was forced to sit out after becoming sick during the day.

Predators 3, Blues 2 — Marcel Goc scored in the fourth round of a shootout to give visiting Nashville the victory over St. Louis, snapping a five-game losing streak.

Red Wings 6, Oilers 2 — Dan Cleary and Tomas Holmstrom each scored twice to help host Detroit beat Edmonton.

Canucks 6, Senators 2 — Daniel Sedin and Alex Burrows each had a goal and an assist, and Henrik Sedin also had 2 points to lead Vancouver’s win in Ottawa.

Sharks 2, Islanders 1 — Dan Boyle scored the tying goal on a second-period power play and added the shootout winner in host San Jose’s victory over New York.

Kings 3, Stars 1 — Justin Williams scored the tiebreaking power-play goal with 13:09 to play, Jonathan Quick made 27 saves and Los Angeles matched the best home start in franchise history with a victory over Dallas.