Ginepri, the former Wheeler High School star who now lives in Kennesaw, led 5-4 in the third set before being broken by the tournament’s defending champion. Isner used that momentum to win and advance to a quarterfinal with eighth-seeded Marinko Matosevic of Australia, who beat American Tim Smyczek 6-4, 7-5.
Ginepri, whose world record is now 281 after a peak of 15 following his run to the U.S. Open semifinal in 2005, was in the tournament as a wild card, but he seemed in position to upset Isner, the top-ranked American at No. 12.
After taking the first set, Ginepri was in position to take the second and complete the sweep, but Isner rallied back to force a tiebreak.
The 31-year-old Ginepri was in a good position throughout, despite Isner holding a 30-8 advantage in aces.
Ginepri fell to 1-3 all-time against Isner. The lone win came in the semifinals of the 2009 Indianapolis Tennis Championships, which Ginepri went on to win for his most recent ATP Tour title.
The Indianapolis tournament then shifted to the Atlanta area for 2010, with Isner having since become a three-time finalist.
In other matches, Dutchman Thiemo de Bakker beat second-seeded Kevin Anderson of South Africa 6-4, 7-5. De Bakker retired from his final qualifying match because of a sore neck and still made the field as one of three “lucky losers,” following the late withdrawals of Gaels Monfils, Richard Gasquet and Radek Stepanek.
De Bakker, ranked 142nd in the world, overcame a 5-3 deficit in the second set.
Ben Becker of Germany also had an upset win, topping seventh-seeded Yen-hsun Lu of Taiwan 6-4, 6-3.