NEW YORK -- It took until their postseason hopes were imperiled, but the New York Islanders are finally playing like a playoff team against playoff-caliber teams.

Andrew Ladd and Anders Lee scored 43 seconds apart early in the third period Tuesday night, when the Islanders killed two penalties in the final six minutes to preserve a 4-3 win over the Washington Capitals in front of a boisterous sellout crowd at Barclays Center.

With their third straight win, the Islanders (14-14-6) climbed out of last place in the Metropolitan Division and moved within 10 points of the Capitals in the Eastern Conference wild card race.

"Listen, we know we're a better team in here than probably our record indicates," said Ladd, who also scored in the second period in producing his first multi-goal game since signing with the Islanders in July. "Obviously, you are what your record is, but we know there's a lot of improvement in terms of what we can do as a group in here and the talent that we have in here."

The Islanders have exhibited some of that improvement and talent over the last month. New York began Nov. 28 with the fewest points in the NHL but has gone 8-4-2 since then, including 7-4 against clubs currently occupying playoff position.

"For whatever reason, I think our best games are usually against the top teams -- it seems to bring the best out of us," Ladd said. "It's going to be important for us going forward to have that confidence playing whoever we're playing."

The Islanders' Cal Clutterbuck and the Capitals' Justin Williams traded goals in the first. New York failed to convert on four power play opportunities in the second but took the lead on Ladd's even-strength goal with 5:57 remaining.

Alex Ovechkin put back a shot by Williams just 1:17 into the third to tie the game, but Ladd scored at 4:41 to give the Islanders the lead for good.

Ladd has four goals in his last six games and has seven goals overall in 34 games -- just two fewer goals than he had through 34 games last season, when he finished with 25 tallies.

"To me, it's once you're a scorer, you're a scorer," Islanders head coach Jack Capuano said of Ladd. "So they're going to come. And we talked about even last year, they came in bunches after Christmas."

Ladd's goal was in the process of being announced when Capitals defenseman Matt Niskanen whiffed trying to pass the puck at center ice. Lee swooped in, picked up the loose puck and beat Braden Holtby on a breakaway.

"We had it tied up and then they pull away from us a little bit," Capitals head coach Barry Trotz said. "And we were chasing the game from that point on."

The Capitals cut the gap to 4-3 when Andre Burakovsky scored with 6:55 remaining, but New York goalie Jaroslav Halak (31 saves) stopped the final eight shots he faced, including four during power plays created by Dennis Seidenberg's slashing penalty with 5:15 left and Thomas Hickey's high-sticking penalty with 2:59 to go.

"Sometimes that's the way it goes -- you've got to pick the power play up when they can't get one and they've got to pick us up when we let one in," Clutterbuck said.

The Capitals came closest to scoring with 25.1 seconds remaining, when Halak turned back a point-blank backhand shot by Jakub Vrana.

Holtby made 27 saves for the Capitals (20-9-4), who have lost three of four (1-2-1).

"We played good enough to win, I just need to be better," Holtby said.

NOTES: The Islanders scratched C Casey Cizikas (upper body), who missed his fifth straight game, as well as RW Stephen Gionta and G Thomas Greiss. Cizikas has yet to resume skating. With Greiss out, third-string G Jean-Francois Berube backed up starting G Jaroslav Halak. ... The Islanders have played an NHL-high 22 home games. ... The Capitals scratched D Taylor Chorney, LW Zachary Sanford and LW Daniel Winnik. ... Capitals RW Tom Wilson took a hard hit from Islanders D Johnny Boychuk and was slow to rejoin the play a few seconds before Ladd's second goal. Wilson finished the game and head coach Barry Trotz said he was fine.