The Islanders gave up a couple of shaky goals to fall behind and could not catch up in a 4-1 loss to the NHL-leading Washington Capitals Thursday night at Barclays Center.

Brock Nelson scored early in the second to cut the deficit to 2-1 and the Islanders came agonizingly close to tying the game late in the second period on the power play but could not beat Braden Holtby, who had 34 saves and is now 18-0-2 in his last 20 decisions.

But Nicklas Backstrom picked Marek Zidlicky’s pocket and fed Nate Schmidt for a one-timer past Jaroslav Halak to extend Washington’s lead back to two and Backstrom scored into an empty net with 2:42 to go to seal it.

Alex Ovechkin had the 497th goal of his career in the first, one of two Caps goals that snuck by Halak in the Isles goaltender’s first game since Dec. 21.