Jason Spezza and Milan Michalek each had a goal and two assists as the Ottawa Senators defeated the Washington Capitals 6-5, their 13th victory in the last 14 games.

Ottawa put together strong first and third periods at Scotiabank Place to hand Washington its first regulation loss in the last 16 games. With the score 4-4 entering the final period, Chris Phillips and Alex Kovalev scored successive goals to make goalie Brian Elliott a winner in his 12th consecutive start.

"We knew that even though we were up that we couldn't sit back, and we did a good job," said Spezza. "We kept coming at them and scoring goals and we scored more than them tonight."

The Capitals had gone ahead 4-3 with a three-goal spurt in the second before Chris Neil tied the score late in the period.

Alexander Semin scored a hat trick and drew an assist for the visitors, with Tomas Fleischmann and Jeff Schultz also scoring. Alex Ovechkin drew an assist to extend his point streak to nine games, but Nicklas Backstrom saw his nine-game point streak halted.

Semyon Varlamov struggled in the Washington net in his first NHL start since Dec. 7. The Russian was 12-1-1 at that point but encountered a pair of injuries to halt his momentum.

The Capitals had won 14 straight until an overtime loss in Montreal on Wednesday.

Washington has averaged just under five goals scored over the last 16 games, but the goals are starting to come in bunches the other way. The Capitals have surrendered 16 in the last three games.

"What you're seeing now isn't normal," Capitals coach Bruce Boudreau said. "Their goalie wasn't any good either, but they got more shots and they scored the extra goal."

With Buffalo losing in overtime to Carolina on Thursday, the Senators have overtaken the Sabres atop the Northeast Division, putting Ottawa (35-22-4) in third in the Eastern Conference.

The Sabres do have two games in hand, but Ottawa trailed Buffalo by a double-digit margin in points in mid-January.

The Senators scored on both of their power plays and denied the NHL's top-ranked power play on two Washington advantages.

Ottawa went up 2-0 by the midway mark of the first.

Just seconds after Elliott hugged the post on Boyd Gordon's wraparound, Spezza wired a wrister from the right circle over Varlamov's glove just over six minutes into the game.

Spezza now has 11 goals and four assists in the last 11 games he's played.

The goal started from a faceoff win in Ottawa's own end, and the next one four minutes later came off a clean draw in the Washington zone.

Spezza won the face off back to Michalek, who snapped it home before Varlamov could adjust.

Ottawa defenceman Anton Volchenkov sprawled to block a bid from the sniper Ovechkin, but not long after Fleischmann worked a give-and-go with and beat Elliott with a hard shot.

Still, Volchenkov's work did not go unnoticed.

"Ovie had one shot on goal because Volchenkov blocked 11," Boudreau said.

Varlamov looked like he was beginning to find a rhythm late in the period after denying Mike Fisher's blast from the slot, but he was porous on the goal that made it 3-1 Ottawa with just seven seconds left in the period.

Ottawa forward Chris Neil searches for the puck in the crease of Washington goalie Semyon Varlamov Thursday at Scotiabank Place. (Fred Chartrand/Canadian Press)

Alfredsson corralled Spezza's cross-ice pass with his skates and beat Varlamov between the pads for the first of two Ottawa power-play goals.

The Senators killed off an early power play early in the second and Elliott was forced at the five-minute mark to muffle an Ovechkin shot set up by Backtrom's drop pass.

Ottawa defenceman Alex Picard lost his stick to set up the sequence that got the Capitals within a goal at the 6:39 mark. Schultz snapped a harmless looking shot from the point, but it beat Elliott high.

Semin tied it not long after Varlamov made a key save off Fisher. The Russian was set up by good work on the boards from Brendan Morrison and then used traffic on the left side to his advantage for a snapshot at 15:17.

Semin scored 42 seconds later on a high shot from the other side after the next faceoff. For at the least the second goal, Elliott was guilty of falling too early on the play.

Neil got Ottawa back on even terms, his backhand shot with two minutes left in the period on a rebound just crossing the line as Varlamov sprawled.

"If you go down the chart on their team, they have lots of guys that can put the puck in the net," Neil said of the Capitals. "It's one guy after another so it's not just No. 8 that you've got to shut down, there are four or five other guys as well."

The Senators had the Capitals on the run early in the third, with Phillips unleashing a slapper off defenceman John Erskine's stick and past Varlamov.

With Ovechkin in the box for interference at the seven-minute mark, Filip Kuba and Michalek set up Kovalev's low slapper goal to restore a two-goal lead.

There was end-to-end action with seven minutes left, the sequence punctuated by a Washington goal. Semin barely missed on a mini-breakaway and then scored through traffic, with Spezza denied in between on Varlamov's save.

Semin now has 29 goals. It was the third consecutive game in which a Washington player scored a hat trick, following Ovechkin on Sunday against Pittsburgh and Brooks Laich against Montreal on Wednesday.

The Capitals buzzed late in the third, but Mike Knuble's attempt to stuff it inside the post was thwarted by Elliott.

Elliott made 19 saves, while Varlamov stopped 22 shots.

Ottawa is 2-1 in the season series, with the home side winning each time.

The Senators will play 14 of their final 21 regular-season games on the road, beginning with weekend affairs in Detroit and the New York Islanders.

With files from The Canadian Press