Capitals defenseman Mike Green and goalie Michal Neuvirth react after Tampa Bay captain Vincent Lecavalier scores to end the game. (Toni L. Sandys/The Washington Post)

Every extra drop of adrenaline provided by Alex Ovechkin’s game-tying, overtime-forcing tally was coursing through the Washington Capitals in extra time of Game 2 of their Eastern Conference semifinal series. They dominated play and sparked bedlam from the capacity crowd behind them, but all the momentum of that setting wouldn’t prevent the Tampa Bay Lightning from taking advantage of one mistake.

Veteran defenseman Scott Hannan thought he could get off the ice for a change and his replacement, Jeff Schultz, would be in position before the puck made its way back to the Capitals’ end. The Lightning noticed the change and quickly turned up ice.

With 6 minutes 19 seconds gone in overtime Sunday night at Verizon Center, Vincent Lecavalier sent a shot above Michal Neuvirth’s glove on a two-on-one as a result of the change to seal a 3-2 Tampa Bay victory. The Lightning holds a two-games-to-none lead as the series shifts to Florida for Games 3 and 4 on Tuesday and Wednesday.

“I thought the puck was going in behind,” Hannan said. “When you make mistakes, it costs in the playoffs. I was a little tired and thought I could get off in time, but obviously, I couldn’t. It was a bad play.”

The Capitals had managed to put forth a better all-around performance than in the series opener, but a sterile power play prevented them from taking any tangible control over the game once again.

Goalie Dwayne Roloson completed a critical 35-save outing for the Lightning, who were able to capitalize off bounces and Washington’s mistakes thanks largely to the calmness it developed having now won five consecutive postseason games, with four of those victories coming on the road.

It was that ability to stay the course, even with pandemonium erupting from those clad in red when Ovechkin knotted the score at 2 with just less than 68 seconds remaining in regulation to force the extra time, that Coach Guy Boucher credited for Tampa Bay’s success.

“I think over the course of these playoffs what the players and this team has learned is to stay calm under pressure and that’s what the players did,” Boucher said. “We reloaded and I always believe it’s not about momentum, it’s about desperation.”

When the Capitals pulled Michal Neuvirth (20 saves) late in the third and Ovechkin scored, they were the desperate team. But after so many missed scoring chances both at even strength and on the power play it begged the question of if they should have been in that situation in the first place.

Washington’s conscious effort to correct its errors of Game 1 was apparent from the start. The Capitals chased down loose pucks and found ways to beat the Lightning’s smothering system, but none of that sparked the power play. The unit failed to convert on another six tries Sunday.

The more the power play sputtered, the more Roloson seemed to grow in steadfastness. At times, Tampa Bay’s grizzled netminder put his unorthodox style on display, twisting and turning to make improbable saves along with routine ones to stop any shot taken against him, including Washington’s 12 shots on the man-advantage.

“You’ve got to come up with something,” Mike Knuble said. “It was our undoing last year. It’s what cost us last year. . . . In these tight games, you get one on the power play, that’s like a bonus.”

Aside from three power-play chances that failed to generate much zone presence in the first period, though, the Capitals dictated the play. Regardless of all of the hits they dished out and scoring opportunities they created, though, Tampa Bay carried a 1-0 lead into the first intermission.

With 58.8 seconds remaining in the period, Lecavalier scored his first goal of the night when he ripped a one-timer from the right faceoff circle that hit the camera inside the net.

At the start of the second the Capitals came out in search of chances against Roloson, who thwarted opportunities from Alexander Semin and Nicklas Backstrom in the opening minutes of the period.

With just more than five minutes remaining in the second period, the Capitals finally forced a bounce to go their way. Backstrom wristed a shot on net that hopped up and over Roloson’s shoulder down to the blue paint where Brooks Laich knocked the rebound over the goal line to knot the score at 1-1. It was Laich’s first point of the postseason and Backstrom’s first point since Game 3 of the quarterfinal matchup against the Rangers.

Tampa Bay received the benefit of the next bounce, however. Martin St. Louis was trying to pass across the crease to Lecavalier when the puck banked off Mike Green’s skate and made an abrupt left turn into the net. The goal pushed the Lightning ahead with 12:25 left in the third.

While the Capitals forced their way back to tie and prompt a third trip into extra time this postseason, they weren’t able to wrap up a victory and now face a critical two games in the next three days.

“Well, the series is not over,” Ovechkin said. “We’re going there and we’re going to win two games. It’s going to be hard. Right now, in this situation we have to win.”