WASHINGTON - Alexander Semin scored one of Washington's three power-play goals Thursday night and assisted on both of the others, including Mike Green's go-ahead goal, and the Capitals held on for a 4-3 victory over the Atlanta Thrashers.

Green's 23rd goal, most among NHL defencemen, came off passes from Nicklas Backstrom and Semin and snapped a 2-2 tie 12:25 into the second period.

It came on a man-advantage, as did Washington's first two goals, which came 53 seconds apart in the first period.

But Ilya Kovalchuk scored later in the first on a power play for Atlanta - with the league's leading goal-scorer, Alex Ovechkin, sitting in the penalty box - before Rich Peverly tied it.

After Green put Washington ahead, Eric Fehr added an insurance goal to make it 4-2.