(Blair Gable/Reuters)

For as well as the Capitals played through the first 38 or so minutes Tuesday night in their 3-2 loss to Ottawa, the small breakdowns and little mistakes that compounded afterward showed how easy it is for strong play to be undone.

No matter how much Washington dominated the play in the second period, giving the Senators chances late in the frame and allowing a goal by Jim O’Brien with less than a minute and a half to go before the intermission is a harsh lesson.

“It’s details of the game. You cannot get scored on in the last two minutes of [the period]. They score there, they get momentum out of it and they get the momentum back in the third period,” center Mike Ribeiro said. “Be smarter at the end of periods, don’t give them momentum to come back in the third and try to get that next [goal] too, to put those teams away.”

The Capitals said they shrugged off O’Brien’s goal, which cut their lead to 2-1, and said that during the break they stressed keeping to the plan that helped them dictate so much of the first two periods. Problem was, Ottawa was determined to push harder in the third.

All of a sudden, Washington was turning over the puck and chasing the Senators. The Capitals were the ones scrambling to find ways to regain possession and get out of their own zone, icing the puck and making less deliberate plays.

“I don’t think we were putting pucks where we need to put pucks,” Matt Hendricks said. “And we weren’t getting pucks out of our zone when we needed to. We were giving them those second and third opportunities.”

In the defensive zone, Nicklas Backstrom won a faceoff drawing the puck back toward the goal line. Wojtek Wolski drifted toward Kyle Turris, who lost the draw, giving Milan Michalek time and space against rookie defenseman Tomas Kundratek. Michalek sent a backhander past Michal Neuvirth that tied the game and woke up a restless Scotiabank Place crowd.

While Sergei Gonchar’s game winner on the power play, with Joel Ward in the box on a questionable high-sticking call, didn’t come until 2:30 remained, the Senators were clearly in control of the contest the rest of the way. Washington lacked some of the poise it had early on as it tried to press and regain momentum.

“We were carrying the play we were doing a lot of really good things,” Troy Brouwer said. “We were playing really hard, doing a lot of smart plays and a missed assignment off a faceoff and a tough penalty at the end and that was the result. It hurts now but we did play a good game.”