Ovechkin made it 2-0 at 1:51 of the second period. He took a pass at the edge of the left circle from Connor McMichael, who was behind the net, and scored to the far side for his third goal in his past four games.
Charlie Lindgren made 30 saves for the Capitals (9-8-2), who had lost four of five (1-3-1).
Anze Kopitar scored for the Kings (10-6-4), who had won four straight and had earned points in 10 straight road games (8-0-2). Darcy Kuemper made 23 saves.
Matt Roy gave the Capitals a 1-0 lead when he tipped an Aliaksei Protas point shot past Kuemper from the low slot at 3:41 of the first period. The goal marks Roy’s first point scored against his former team.
Kuemper made 13 saves in the first period, including a pad save on Tom Wilson’s breakaway attempt at 15:25 to keep the Kings within one.
Kopitar, playing his final regular-season game at Capital One Arena, pulled the Kings within 2-1 at 13:27 of the second period, scoring on a tip-in at the far post off Corey Perry’s pass from the right point on a power play.