Asked whether he was surprised that Semin, who had missed the previous seven games, played so well in his return, Capitals coach Bruce Boudreau wisecracked: "He was well-rested. He should have a lot of energy."
Ovechkin served the first of a two-game ban levied by the NHL following his ejection Monday for a knee-to-knee hit on Carolina's Tim Gleason. Some fans in the sellout crowd of 18,277 held signs reading "Free Alex."
"I think it shows we've got some depth," said Washington's Brendan Morrison, who had a goal and two assists. "Obviously, Ovie isn't in the lineup tonight, so it's a chance for other guys to step up and contribute. We got that tonight from several guys."
Scott Clemmensen subbed for injured Florida goalie Tomas Vokoun for the second straight night, but was quickly pulled from the game in favor of backup Alexander Salak. Vokoun was struck in the head by teammate Keith Ballad's stick on Monday.
In other games:
* At Glendale, Ariz., Taylor Pyatt scored with 3:29 remaining to lift Phoenix past the Calgary Flames, 2-1. Petr Prucha also scored for the Coyotes, who won their third straight.
* At Dallas, James Neal and Steve Ott scored 71 seconds apart early in the third and the Stars beat Anaheim, 3-1.
* At Pittsburgh, Sidney Crosby had two goals and an assist for the Penguins, who won for the sixth time in seven games by beating Colorado, 4-1.
* At Atlanta, Matt Moulson scored three goals for his first career hat trick and the New York Islanders snapped the Thrashers' four-game winning streak with a 4-1 victory.
* At Buffalo, Clarke MacArthur, Jason Pominville and Derek Roy scored first-period goals, Ryan Miller made 21 saves, and the Sabres beat the Montreal Canadiens, 6-2.
* At Columbus, Phil Kessel and Jason Blake each scored two goals and Toronto beat the Blue Jackets, 6-3.
* At Detroit, Patrick O'Sullivan scored twice and Jeff Deslauriers made 27 saves to lift Edmonton to a 4-1 win over the Red Wings.
* Chicago's Jonathan Toews and Patrick Kane have signed 5-year deals reported to be worth $31.5 million each, while defenseman Duncan Keith got a 13-year contract worth a reported $72 million, making it the richest in team history.
* Toronto goalie Jonas Gustavsson will undergo his second heart procedure in less than 3 months. In other news, Toronto sent Philippe Paradis to Carolina for Jiri Tlusty in a swap of former first-rounders.