WASHINGTON — If all else fails, John Isner knows he can count on his serve to help him out, especially on hard courts.
The 6-foot-10 American hit 17 aces and won 37 of 40 first-serve points Wednesday to move into the third round of the Citi Open by beating Victor Estrella Burgos of the Dominican Republic 6-3, 7-6 (5).
Isner, seeded eighth at the hard-court tuneup for the U.S. Open, never faced a break point, powering serves that regularly topped 130 mph. The American compiled a 26-9 edge in winners.
The runner-up in Washington in 2007 and 2013, Isner had his left leg massaged by a trainer late in the second set, then was two points from being pushed to a third when the 51st-ranked Estrella Burgos took a 5-4 lead in the tiebreaker.