NEW YORK (AP) — Bob and Mike Bryan opened their pursuit of the first men’s doubles Grand Slam of the Open era with a straight-sets win Thursday.

The top-seeded twins beat Federico Delbonis and Leonardo Mayer of Argentina 7-6 (1), 6-2 as they opened the defense of their title at Flushing Meadows. Coming into last year’s U.S. Open, they hadn’t captured a major championship in more than a year. Now they’ve won four straight.

That made them the first men’s doubles team to hold all four major titles at the same time in the Open era, which started in 1968, and now they’re chasing the calendar year Grand Slam.

The 35-year-old brothers didn’t face a break point Thursday in advancing to face Eric Butorac and Frederik Nielsen.