Eric Fehr scored twice in his return from a 22-game absence because of a shoulder injury, and Jason Arnott had an assist for his 900th career point.
The win pushed the Capitals past the Bruins into second place in the Eastern Conference.
Edmonton, which has the fewest points in the NHL, has lost two in row after winning three straight.
Washington went up, 1-0, with a power-play goal at 5:35 of the second period. After Holtby denied Andrew Cogliano on a shorthanded breakaway, Ovechkin scored from the left of the net after taking a pass from Arnott.
Fehr scored at 10:32 of the period on a rebound of a shot by John Carlson, who had taken a cross-ice pass from Ovechkin.
Lightning 4, Blackhawks 3 — Steven Stamkos scored his NHL-leading 42d goal, Martin St. Louis had the shootout winner, and Tampa Bay snapped a season-high four-game losing streak with a victory over visiting Chicago.
St. Louis also scored in regulation, helping Tampa Bay build a 3-1 lead before the Stanley Cup champions roared back on goals by Patrick Sharp and Jonathan Toews.
Blues 4, Blue Jackets 3 — Chris Stewart flicked in a backhander 54 seconds into overtime to cap St. Louis’s comeback from a three-goal deficit in Columbus.
Stewart’s second goal of the game came as he crashed the net on a rush from the left wing, the puck wafting over the right shoulder of goalie Mathieu Garon.
Kings 2, Red Wings 1 — Dustin Brown scored with 5:17 remaining in the second period and Jonathan Quick made 28 saves in visiting Los Angeles’s victory over slumping Detroit.
Anze Kopitar also scored for Los Angeles in the second after Darren Helm opened the scoring for the Red Wings in the first. Detroit trails Vancouver by nine points for the top spot in the Western Conference.
Ducks 5, Rangers 2 — Corey Perry and Lubomir Visnovsky each had two goals and an assist, Bobby Ryan added a goal and three assists, and host Anaheim beat New York.
Defenseman Visnovsky increased his points total to 54 — tying Detroit’s Nicklas Lidstrom and Phoenix’s Keith Yandle for the NHL lead at the position.
Flames 4, Stars 3 — Curtis Glencross scored in the third round of the shootout to give Calgary the victory in Dallas.
Alex Tanguay scored in the second round, but Dallas’s Mike Ribeiro countered on a nifty move in the third round to set the stage for Glencross.
Thrashers 3, Hurricanes 2 — Tim Stapleton scored 1:38 into overtime to give Atlanta the victory over host Carolina.
