Tampa, FL – Steven Stamkos scored his NHL-leading 40th goal 1, on Saturday night.
The Lightning have won two in a row and were coming off Thursday's 6-5 victory over San Jose in overtime.
"We isolated this game. Nothing before and nothing after. It was just one game against Washington," said Lightning coach Guy Boucher. "There was a few things we wanted to do better, namely not allow five goals."
Capitals defenseman Mike Green, after missing more than a month because of stomach surgery, played 14 minutes in his first game since January 7 and said he "felt fine."
"I think they scheduled me to come back so I could have an off day tomorrow," he said. "That's the plan and I think we'll stick with it."
The Lightning took a 1-0 lead 2:10 into the game after a neutral zone turnover by the Caps. Teddy Purcell's shot got through Vokoun and Pyatt was behind him to tap it in.
Garon had eight saves to keep Washington off the board in the period and the Lightning scored again after another turnover in the second.
Stamkos did it himself, stealing the puck near the blue line and skating down the ice on a breakaway before deking to his forehand to beat Vokoun at the 1:50 mark.
Laich pulled the Capitals within 2-1 midway through the period at the end of a tic-tac-toe play.
Alexander Semin started it, slipping a pass from the low right side to Mathieu Perreault in the slot. Perreault then directed it to Laich near the crease, and he scored into the empty side of the net.
The Capitals, who were coming off a 2-1 win over Southeast Division-leading Florida on Friday, fell to 4-6-3 in their last 13. They had won four of the previous five meetings with Tampa Bay, including two of three this season.
The Lightning improved to 3-3-1 in their last seven games overall and have won two straight.
The Capitals are 1-1 on a four-game road trip that continues Monday at Carolina...The Lightning are 2-1 on a four-game homestand that ends Tuesday versus Anaheim.