TAMPA, Fla. -- The Washington Capitals wasted a chance to enhance their push toward the playoffs.
Stamkos gave the Lightning a 3-2 lead with 1:03 left, just 2:14 after Jason Chimera tied it for Washington, when he put in a rebound after goalie Michal Neuvirth had stopped Brett Clark's shot from the blue line. Stamkos then scored into an empty net at 19:58.
"We're fighting for our playoff lives, so it's not that hard to bounce back," Chimera said. "It means a lot playing for something this time of year. You want to play in the playoffs. Ask any player what is the worst day. It's sitting home watching the first day of playoffs. You want to be in those playoffs. You want to be in the hot seat."
Washington, which also got a goal from Alexander Semin, is in eighth place in the Eastern Conference. The Capitals have a two-point lead over the Buffalo Sabres with two games remaining. The Sabres have three games left.
"It's disappointing to say the least," Washington right wing Troy Brouwer said of the loss.
The Capitals are three points behind Southeast Division-leading Florida. The teams play in Washington on Thursday night.
"We were too lackadaisical," Capitals defenseman Karl Alzner said. "We should have come out and tried to pound them right away and get their spirits down."
"It was nice to beat a divisional rival in a game that mattered to them," Stamkos said. "When you're in the position we are, you just play spoiler. You try to win every game. I don't think you come into games with grudges against certain teams, but after it's that much more sweet to win, especially our last game at home and against a team that we've battled with the last couple years."
Chimera tied it at 2 with his 20th goal of the season, coming from in-close with 3:17 left in the third.
Purcell and Hedman had goals 25 seconds apart late in the second. After Purcell scored from the left circle during a power play with 2:40 to go, Hedman beat Neuvirth with a shot from the blue line that put the Lightning ahead 2-1 at 17:45.
Semin gave the Capitals a 1-0 lead from the top of the right circle following a Tampa Bay turnover at 12:47 of the second.
Tampa Bay's Dwayne Roloson stopped several good scoring chances in first, including shots from Alex Ovechkin and Mike Knuble. He made an outstanding second-period glove save on Mike Green, who whacked his stick on the glass in frustration.
"Everyone on their bench, our bench, thought it was a goal," Stamkos said. "I'm sure Green thought it was a goal, too."
Roloson made 31 saves.
Neuvirth stopped a shot from the slot by Stamkos, and rookie J.T. Brown's in-close chance during the second.
"This was a playoff atmosphere," Lightning coach Guy Boucher said.
Tampa Bay finished with 27 shots.
Stamkos added an assist, giving him three assists and 11 points during a six-game point streak. ... Semin, who also had an assist, has 23 goals and 43 points in 39 games against Tampa Bay. ... Purcell snapped his 11-game goal drought, dating to March 8 against the Capitals. ... Washington G Tomas Vokoun is out with a groin strain. He has played just once -- for 18 minutes last Thursday -- in nine games. ... Lightning C Nate Thompson earned his first assist in 26 games when he helped set up Hedman's goal. ... Stamkos and Ovechkin had six shots each. Brown, playing in his second NHL game, had five shots.