Washington Capitals\' Matt Pettinger (18) celebrates Chris Clark\'s (17) game-winning goal against the Ottawa Senators during the overtime period of a hockey game, Monday, in Washington. The Capitals won 4-3.(AP Photo/Nick Wass)
Ovechkin scored a power-play goal with 24.4 seconds left in regulation to tie it. Ottawa defenceman Chris Phillips was whistled for tripping with 1:03 to play and the visitors clinging to a 3-2 lead.
Clark then scored 1:33 into the extra period off an assist from Alexander Semin, who also assisted on both of Ovechkin's goals. Ovechkin, the reigning Calder Trophy winner as the league's top rookie, redirected a shot by Semin 7:56 into the second period to cut Washington's deficit to one goal.
Ottawa led 3-0 less than 12 minutes into the game, chasing Washington goalie Olaf Kolzig after only five shots.
Daniel Alfredsson had a goal and an assist for the Senators. Dany Heatley and Antoine Vermette also scored and Andrej Meszaros had two assists in that spurt, which prompted Washington coach Glen Hanlon to call timeout and yank Kolzig, replacing him with backup Brent Johnson.
It was Kolzig's shortest outing since March 8, 2003, when he allowed three goals in 10 minutes against Boston.
The Senators have lost four straight to fall to 5-7-1 with 40 goals; at the same point a year ago, Ottawa was 11-2 with 64 goals.
The Senators held a closed-door meeting after their last game, but it didn't help and Ottawa's unbeaten streak at Washington ended after eight games, dating to the 2001-02 season.
Johnson shut down the visitors while he was on the ice, stopping all 21 shots he faced. He helped Washington improve to 1-5 in one-goal games this season.
Ottawa went ahead after 1 1/2 minutes, when the Capitals gave up the puck in their own end, and Jason Spezza set up Alfredsson's goal. At 10:25, Alfredsson passed to Vermette, who skated from left to right in front of the goal before netting a backhander to make it 2-0. The Senators padded the lead at 11:51, when Anton Volchenkov sent the puck around the boards and Kolzig failed to clear it completely, allowing Heatley to come in 1-on-1 and push a shot between Kolzig and the near post.
But Ottawa goalie Martin Gerber gave up the big lead.
Washington got on the scoreboard with 45.8 seconds left in the first period. On a power play, Jamie Heward's shot from the point deflected into the net off Matt Pettinger, who was credited with his first goal of the season.
Eventually, Ovechkin brought Washington all the way back.
With 18 points through 14 games, Ovechkin is three points ahead of his pace in 2005-06, when he wound up with 106. He has four consecutive multiple-point games.
Notes: There were only six penalties called, four on Ottawa. . . . Attendance was 10,845. . . . Alfredsson has 24 goals and 18 assists in 37 career games against Washington. . . . Ottawa opened a four-game road trip. . . . Senators D Wade Redden missed a fourth consecutive game with a groin injury. He's listed as day-to-day. . . . Capitals RW Richard Zednik was out for a second game in a row. The team isn't saying what sort of injury he has.