Fernando Pisani, Joffrey Lupul and Marty Reasoner also scored for the Oilers who were coming off a pair of 6-2 losses on a two game road trip to Anaheim and Phoenix.
With the victory the Oilers improve to 6-0 at home and 7-4 overall while the Capitals drop to 3-3-4.
The Oilers kicked off the scoring midway through the first period when Ryan Smyth blasted a slapshot to the top corner that blew by Capitals starter Brent Johnson. The power-play goal was Smyth's sixth goal of the season.
The Oilers outshot the Caps 10-3 in the first period, the only real sniff on offence for Washington came when Oilers goalie Dwayne Roloson was forced to make an acrobatic glove save on a hard
wrist shot from Alexander Ovechkin.
The game remained at 1-0 through a scoreless second period, the best chance coming late in the second when Washinton's Brian Pothier ripped a point shot that hit the post.
The Oilers took a two goal lead five minutes into the third when defenceman Marc-Andre Bergeron drifted a knuckleball at the Capitals net and Fernando Pisani tapped it in.
Edmonton put the game away with just under four minutes left when Johnson allowed a big rebound on a Petr Sykora shot and Joffrey Lupul capitalized for a power-play goal.
Marty Reasoner added an empty-net goal to cap the scoring.
It was the first time Ovechkin played against Edmonton. The only team last season's rookie of the year hasn't faced is Calgary. He'll get a crack at the Flames on Tuesday.
Notes - The last time these two teams met was way back on January 11, 2004 when the Capitals defeated the Oilers 1-0 at MCI Center in Washington . . . The Caps lost their previous six games in
Edmonton, outscored 31-11 over that span . . . Entering the game against the Oilers, the Caps had scored eight power play goals this season and seven had been scored by either Semin or Ovechkin.
Semin led Washington with eight goals. Last season, the Capitals did not have a player other than Ovechkin get eight goals until Matt Pettinger scored on December 23. . . . Oilers forward Jarret Stoll
recorded his 100th career NHL point with an assist in the first period.