Backstrom made it 3-0 when he redirected a pass from Jakub Vrana for a power-play goal 28 seconds into the third period. Washington was 2-for-4 with the man-advantage.
"Just quickly as we were heading out to the ice, we just mentioned how big it would be to that power play to be ready to execute right off the bat, and that was really quick, really well done, and it was important," Laviolette said. "At 2-0, that next goal, I feel like in a two-goal game that next goal is always a big goal and for it to go our way was important."
Oliver Wahlstrom scored on a wrist shot from the slot for a power-play goal at 4:17 for the 3-1 final. It was Wahlstrom's second goal in the past three games.
"Samsonov played a really good game," Wahlstrom said. "You can see he's really good at his angles and he's a big goalie, so it was tough to get one by him today. He played a really good game."
NOTES: Ovechkin also had an assist and became the 35th player in NHL history to score 1,300 points; he has 1,301 in 1,177 games and trails Marcel Dionne by 13 goals for fifth on the all-time list (731). … The Islanders are 0-3-0 against the Capitals this season. Each game has been played at Washington.