Dainius Zubrus had a goal and an assist, and the Capitals dominated the Islanders again with a 4-1 victory Tuesday night that sent New York to its sixth straight loss.
Kip Miller, Jaromir Jagr and Joel Kwiatkowski also scored for the Capitals, who became the last NHL team to win consecutive games this season.
"It wasn't lost on us," Capitals goalie Olaf Kolzig said. "We've been awful for the first two months, but now we're starting to turn it around a bit."
Kolzig turned aside 25 shots, allowing only Arron Asham's goal in the victory.
"I think we're on the way up, and they're on the way down," Kolzig said. "A few weeks ago, they passed us, but we seem to be headed in opposite directions."
Garth Snow made 21 saves for the Islanders, 1-24-3-1 in their last 29 meetings with Washington.
The Capitals took advantage of a four-minute, high-sticking penalty to Oleg Kvasha by scoring twice.
Miller made it 1-0 at 3:19 when Kvasha and Islanders teammate Roman Hamrlik were both in the penalty box. At the right crease, Miller's wrist shot ticked off the tip of Snow's glove and went in.
Jagr made it 2-0 at 5:59 when he deflected Dainius Zubrus' centering pass past Snow. It was Jagr's 10th goal this season.
"We figured if we got that first goal, we might have them," Capitals coach Bruce Cassidy said. "They're going through some of the stuff that we went through, so we know."
Kwiatkowski scored an easy goal at 9:41, skating in uncontested on Snow and putting a backhander into the open net to make it 3-0.
After a scoreless second period, Zubrus broke in alone and beat Snow with a high wrist shot 61 seconds into the third.
The Islanders (9-12-2) ended Kolzig's shutout bid 1:53 later when Asham fended off defenseman Brendan Witt and made a backhand-to-forehand move to bring New York within 4-1.
Islanders captain Michael Peca has just two goals this season, none since Nov. 6. "Obviously, our situation is worse," Peca said. "We've addressed every angle and every little thing, and there always seems to be one straw that breaks our back."