Zubrus got his stick on the puck as it lay tantalizing close to the goal line, having trickled past goalie Mathieu Garon and off the right post following a shot by Alexander Semin. It was Zubrus' 19th goal.
Boyd Gordon, Ben Clymer and Chris Clark also scored for the Capitals, and Alex Ovechkin earned a second-period assist to end the longest scoring drought of his young career - he had gone three games without a point.
Anze Kopitar, Alexander Frolov and Lubomir Visnovsky scored for the Kings, who lost to the Capitals on the road for the first time in nearly nine years. They had gone 4-0 with one tie at the Verizon Center since a 3-2 loss on April 4, 1998.
The game was as close as one could expect from two struggling teams. The Kings entered the game having lost 11 of 13, while the Capitals had dropped nine of 12.
Kings rookie Kopitar scored the only goal of the first period, a rebound off the far post during a 5-on-3 power play.
But Garon, giving 40-year-old Sean Burke a night off, allowed three goals in a rough second period. He whiffed glove-side on Gordon's short-handed shot from the blue line, was slow to react on a wraparound by Clymer and let a close-in shot from Clark trickle over the goal line. Ovechkin got the second assist on Clymer's goal.
The Kings kept pace with a redirect from Frolov, his 29th goal of the season, and a one-timer from Visnovsky. Michael Cammalleri, who missed Tuesday's shootout loss at Tampa Bay with a muscle strain, assisted on both goals.
Los Angeles failed to score during a 5-on-3 power play that lasted 1:05 in the second period, and the teams went scoreless in the third.
Notes: Ovechkin played 136 games before having his first three-game stretch without a point. According to the Elias Sports Bureau, only two players in NHL history have had longer streaks at the start of their careers: Mario Lemieux (735 games, 1984-97) and Kent Nilsson (183 games, 1979-82). ... Cammalleri's two assists gave him 31 on the season, a career high. He also has a career-high, seven-game point streak.