NEW YORK -- Washington Capitals coach Barry Trotz used a literary reference Thursday night to explain the familiarity his team has with the New York Islanders.

"We've played a lot of games against each other," Trotz said. "They've got a good book on us. We've got a good book on them."

The Capitals probably like the ending of their book a lot more than the Islanders like the ending of theirs.

Right winger Justin Williams scored with 43.2 seconds left in overtime as the Capitals continued a nearly year-long mastery of the Islanders with a 3-2 win at Barclays Center.

The Capitals have followed up a seven-game win over the Islanders in last season's Eastern Conference quarterfinals by winning all three meetings between the teams this season. Only once in those three games were the two teams separated by more than two goals: Washington center Nicklas Backstrom scored an empty-netter with 2:42 left to ice a 4-1 win at Barclays Center on Jan. 7.

In last spring's series, the Capitals and Islanders were separated by one goal for a total of just 60 minutes and 23 seconds.

"Every game has been a real good battle," Trotz said. "They've been close games, they've been exactly what we had last year. They have a good hockey team. I think we have a good hockey team."

As they have done against the Islanders over the past 10 months, the Capitals continued to contain one of the most potent offenses in the league. New York, which finished third in the NHL in goals last season and entered Thursday with the eighth-most goals, has scored two goals or fewer in all three games against Washington this season and in seven of the 10 games dating back to last April.

The Islanders got off to a quick start Thursday by producing the first six shots of the game and the first goal -- a nifty score by center John Tavares in which he switched from a backhand to a forehand while eluding defenseman Nate Schmidt and poking the puck between the legs of goalie Braden Holtby. However, New York collected just 13 shots in the final two periods and overtime combined.

"They have a lot of speed and they can play a physical game," said Holtby, who finished with 20 saves. "I thought we took that away better tonight with how we moved the puck. We got back into our zone, gave our defenseman options all the time. That's how you beat that speed (and) physical game."

The Capitals took the lead when left winger Alex Ovechkin scored his NHL-leading 36th and 37th goals just 87 seconds apart early in the second. Center Evgeny Kuznetsov set up the first goal with a whirling pass from behind the net to a wide-open Ovechkin, who poked it into the right corner of the net as Islanders goalie Thomas Greiss was caught leaning to the left.

"I was surprised, puck came right on my stick," Ovechkin said. "I just have to do my thing and don't miss the empty net."

Ovechkin gave the Capitals the lead 2:52 into the period, when he took a no-look stick pass from Backstrom and fired a shot past Greiss, who was screened by Backstrom and Islanders defensemen Travis Hamonic and Brian Strait.

"It was tough because the momentum in the second period -- just seemed like we couldn't get back into our rhythm," Islanders coach Jack Capuano said.

The Capitals were 1:44 away from escaping with a regulation win when Islanders center Frans Nielsen tied the game by putting back the rebound of a shot by left winger Kyle Okposo.

Washington controlled the overtime before Williams' one-timer sailed past Greiss. The Capitals (42-10-4) have won seven of eight (7-1-0) to move seven points ahead of the Chicago Blackhawks in the race for the Presidents' Trophy.

"I liked a lot in that game," Trotz said. "I thought Greiss made some good saves at key times, and we just never pulled away. They hung around, they got a late goal there, but really we didn't give up too much. I'll take that game every night, for the most part."

Greiss made 35 saves for the Islanders (30-19-7), who are one point ahead of the Pittsburgh Penguins in the race for third place in the Metropolitan Division and two points ahead of the East's second wild-card position, currently held by the New Jersey Devils.

The Islanders now head into a seven-game road trip -- tied for the longest in franchise history -- that begins Friday night in New Jersey.

"It's a good point," Capuano said. "'Fransie' came up big for us at the end."

NOTES: The Islanders scratched D Calvin De Haan, RW Steve Bernier and G Jean-Francois Berube. De Haan is day-to-day with a lower-body injury he sustained Monday in a 4-1 win over the Detroit Red Wings. ... The Islanders' upcoming road trip is the fifth seven-game trek in franchise history. They will go 18 days between home games, a stretch matched only by a seven-game trip in 1981-82. ... The Capitals scratched D Taylor Chorney and RW Stanislav Galiev. ... The Capitals' streak of 20 straight games with at least one third-period goal ended, two shy of the franchise record set during the 1983-84 season.