The Russian forward tied the game in the third before adding the shootout winner as the Capitals beat the Toronto Maple Leafs 5-4.
``It's funny: He was sick tonight, and we didn't know if he would be scratched until after warmup,'' Capitals coach Bruce Boudreau said. ``He said he wanted to play - and he becomes the hero.''
Good thing for the Capitals, who improved to 4-0-0 when Semin scores this season.
He also contributed his fifth assist, while tying two-time league MVP Alex Ovechkin for the team lead in goals. Semin has eight points in Washington's past five games.
Toronto has lost four consecutive games, and seven of its last eight.
The Capitals led 3-1 heading into the third period before Mike Brown
, Kris Versteeg and Tyler Bozak
scored in a span of 3:03 for the Maple Leafs (5-5-2).
``The third period, I thought we played great,'' Toronto coach Ron Wilson said. ``We pressured the puck, had a good power play, scored some goals, took the lead.''
But then Ovechkin and Semin combined to knot the score 4-4 with under six minutes to go.
Washington's Brooks Laich got his stick on Ovechkin's shot as it bounced around near the net before Semin corralled the loose puck and beat Leafs goalie Jonas Gustavsson
from a difficult angle.
``There's not too many guys in the National Hockey League that have hands like that - that can pick it and put it there that quickly,'' Boudreau said.
Overall, the Capitals went 2-for-4 on the power play and now have five extra-man goals in the last two games after scoring just four in the season's first 10 games.
In the shootout, Semin and Ovechkin scored, while Capitals goalie Michal Neuvirth stopped both of Toronto's attempts. It was rookie Neuvirth's first NHL shootout victory.
``He's incredible. I don't want to pump him too much, but he's been outstanding for us,'' Washington's Mike Green said about his goalie. ``As a defenceman, I feel so comfortable with him behind us. There's already a mutual bond that we feel even though he's only been here a short period of time.'' Nikolai Kulemin
gave the Leafs a 1-0 lead with a goal at the 14:29 mark of the first period before Green, Jason Chimera and Tomas Fleischmann scored for Washington (8-4-0) in the second.
Then it was Toronto's turn to score in a hurry, something the Maple Leafs haven't been doing much lately. In their previous game, they ended a goal drought of 167 minutes 39 seconds, the franchise's longest in 83 years, according to the Elias Sports Bureau.
``Hockey is a game of emotion, and when you've got a team that's down 3-1 and they think they're out of it or it looks like they're out of it, they get a goal and then they get pumped up,'' Boudreau said. ``They come up, and we get down.''
But not for long, thanks in large part to Semin, and now Washington has won four of its past five games. NOTES:
Ovechkin had two assists. ... The Leafs were playing the second game of a back-to-back set; they lost at home to the Ottawa Senators 3-2 Tuesday night, when Toronto captain Dion Phaneuf
was sidelined for what could be more than a month with a left leg injury. ... Toronto hadn't scored more than three goals in a game since Oct. 15, when it beat the New York Rangers 4-3 in overtime. ... Neuvirth entered the game already tied for the NHL lead with seven wins and earned rookie of the month honours in October. ... Brown was credited with seven of Toronto's 28 shots.