Connor McDavid scored the winner on a breakaway 47 seconds into overtime, taking Bouchard's clearing pass from out of the defensive zone and lifting a backhand over Washington goalie Charlie Lindgren at the net for his second goal of the game.
McDavid and Leon Draisaitl each had three assists for the Oilers (26-19-8), who had lost two in a row. Connor Ingram made nine saves on Washington’s first 12 shots before being pulled for Tristan Jarry, who stopped 13 of 15.
Connor McMichael and Justin Sourdif each had a goal and an assist, and Tom Wilson and John Carlson each had two assists for the Capitals (25-21-7), who have lost five of their past six games (1-4-1). Lindgren made 34 saves.
Bouchard put the Oilers up 1-0 with 48 seconds left in the first period, taking a cross-ice pass from Mattias Ekholm and scoring on a wrist shot from the point off the left post.
Just 22 seconds later, Aliaksei Protas tied it 1-1, picking up the rebound off a shot from the slot by Rasmus Sandin and backhanding it past Ingram’s extended stick at 19:34.
The Oilers outshot Washington 10-2 in the opening period.
Bouchard gave the Oilers a 2-1 lead at 4:13 of the second period, with another wrist shot from the high slot that went in off Lindgren’s glove. The goalie ended up tossing his trapper into the net as he reached back for the puck.
Draisaitl recorded the 600th assist of his career on the play.
Sourdif tied it 2-2 at 6:50 on a 2-on-1 rush alongside McMichael, winning a chase for the puck in the neutral zone and then pulling up at the left dot to take a wrist shot that beat Ingram near post.
Anthony Beauvillier gave Washington a 3-2 lead at 14:29, sending a wrist shot from the boards at the far edge of the left circle that bounced off the skate boot of Oilers defenseman Spencer Stastney and through Ingram’s legs.
Bouchard tied it 3-3 at 4:30 of the third period, skating into the slot and firing a wrist shot high off the left post.
Dylan Strome put Washington ahead 4-3 on the power play at 6:40 with a wrist shot from the point that deflected in off Stastney.
McDavid tied it 4-4 on the power play at 8:24, skating cross-ice into the left circle before sending a wrist shot in off of Lindgren’s left arm for his 31st goal of the season.
It was McDavid’s first goal in eight games.
McMichael put Washington ahead 15:09, taking four whacks at the puck in the crease before putting it past a seated Jarry.
Zach Hyman scored with 32 seconds left in the game, deflecting a centering pass from McDavid in the crease to force overtime.
Sandin had to be helped off the ice late in the first period after blocking a shot by Oilers defenseman Ty Emberson.
