ATLANTA (AP) Two-time defending champion John Isner beat Radek Stepanek 7-6 (3), 7-6 (7) on Thursday night in his opening match in the Atlanta Open.
The top-seeded Isner has made the Atlanta finals four of the last five years, winning the last two after losing to Mardy Fish in 2010 and 2011. Yet, this was the first time in six Atlanta appearances that he was not taken to three sets in his first match.
Still, Stepanek - previously 4-1 against Isner - stretched both sets only to see Isner move to 12-1 in Atlanta tiebreakers since 2012.
While Isner's booming serve was good for 33 aces to three for Stepanek, it was a good thing the world's 19th-ranked player was at ''home.'' Fans in Atlantic Station favored the former University of Georgia star, especially when the former Bulldog trailed in the second.
''(With) the Georgia fans, the barks in the crowd, it feels like I'm playing a college match,'' Isner said after moving to 17-3 in Atlanta. ''It's a very comfortable atmosphere. I played a pretty nervous match, to be honest.''
Isner took the first set with his 17th ace, but Stepanek - a 36-year-old, 20-year pro from the Czech Republic - broke registered the first service break of the match when he launched a forehand winner to lead 3-2 in the second set.
After trading holds, Isner broke back in a game where he turned his back to the net and ran to save a deep ball by popping it high in the sky. That set up an eventual passing shot that surprised Stepanek.
''I certainly got lucky right there,'' said Isner, who now lives in Tampa. ''He hit it right back at me and I was able to hit a winner. He had some double faults in that game as well.''
Earlier, qualifier Denis Kudla upset third-seeded Jack Sock 7-6 (6), 6-3, and No. 6 Steve Johnson and No. 8 Benjamin Becker also tumbled out.
Sock, an American ranked 35th, fell quickly in the second set when his service game abandoned him and high humidity and temperatures in the mid-90s slowed him down.
The 94th-ranked Kudla was 5-7 in ATP matches, although he reached the round of 16 at Wimbledon a month ago. Sock was 17-8.
''I've been in the heat now for four days,'' Kudla said of the benefit of having played through qualifying. ''I'm glad I was able to take advantage of the opportunity knowing it was his first match and he had no rhythm.''
Israel's Dudi Sela, who fell in the 2014 final to Isner, beat Becker, from Germany, 7-5, 6-3, and Ricardis Berankis of Lithuania rolled past Johnson, 6-4, 6-2.
Isner will face Berankis on Friday in the quarterfinals.
The top-seeded doubles team of Bob and Mike Bryan won the nightcap, 7-6 (5), 7-6 (4), over Johnson and Treat Huey. The Bryans rallied from a 1-4 hole in the second-set tiebreaker, winning the final six points.