Alexander Semin scored two goals in a game for the 11th time this season, defenseman Mike Green notched No. 18 and rookie Mathieu Perreault – just recalled from AHL Hershey over the weekend — added his second goal in as many games.

But an early hole was again too much to overcome for Washington (49-15-12, 110 points), which is winless in its last three games. Ottawa forward Jason Spezza finished with a game-high four points, including a first-period goal that helped lift the Senators to a 3-1 lead. And with just 18.9 seconds left in overtime, Ottawa forward Alex Kovalev knocked the game-winner past Caps goalie Jose Theodore (26 saves, 31 shots) on a pass from teammate Erik Karlsson. It was Kovalev’s first point since the Olympic break ended on March 2 – a span of 12 games. The Senators were on a short 4-on-3 power play after Caps center Nicklas Backstrom was penalized for tripping Kovalev with 32.7 seconds to play.

“The difference between last year and this year is last year we were playing teams that were out of the playoffs so our level of play came way down,” said Caps coach Bruce Boudreau. “I think the teams we are playing now are fighting for something. That was a hard-fought game. That wasn’t a go-through-the-motions game or a ‘Let’s get the season over with’ game. You had two teams wanting it. I don’t think our level of play will be dropping like it was last year.”

Washington has now been outscored 9-1 over the last three first periods in games against Ottawa, Calgary and Carolina and seven of those goals have come in the first 10 minutes, 34 seconds of play. For a team that has repeatedly referenced last year’s sluggish end to the regular season that’s an unwelcome development.

“We talked about it. Bruce talked about it. For some reason, I don’t know,” said Caps forward Quintin Laing. “For our team to manage only four shots [in a period] is unacceptable. We have to look back and get some answers and fix it.”

The Caps managed just 14 shots through two periods. But they also entered the third tied at 3 after a breakaway goal by Semin – his second of the game  – and another by Green on the power play just 54 seconds later. That set the stage for Perreault, who scored his second goal in as many games. This time he won the offensive-zone faceoff and drove the net, receiving a pass from teammate Eric Fehr. Perreault then had just enough room to roof a shot past Ottawa goalie Brian Elliott (17 saves, 21 shots) for the go-ahead score. Spezza tied it again at 5:13 of the third period with his second goal. The teams traded quality chances in overtime before Backstrom’s penalty gave Ottawa one last good chance. He thought he had touched the puck. The referees disagreed.

Washington has gone to overtime in 10 of its last 18 games and won just four of those contests. Rookie defenseman John Carlson left the ice midway through the second period and did not return. His last shift ended at 12 minutes, 50 seconds. Boudreau described it as an upper-body injury and said Carlson could play Thursday, if needed. With little to play for now and just six games left in the regular season for that seems unnecessary. But even with their lofty spot in the overall NHL standings, the Caps won’t stand for many more early efforts like this one.

“We played great in the second and third [periods],” Backstrom said. “It’s hard to say. Maybe we’re not ready for the first period. But we have to because I remember last year in the playoffs we weren’t ready the first two games. We have to get ready now and maybe play a good 60 minutes. We haven’t played a good 60 minutes for a while.”

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