This is the time of year that's generally been kindest to 6-foot-9 John Isner and his big serve.
Pounding balls at up to 142 mph, the highest-ranked American man hit 18 aces and never faced a break point Friday during a 6-7 (5), 6-4, 6-4 victory over Marcos Baghdatis of Cyprus that put Isner in the Citi Open semifinals.
Isner won for the 10th time in his last 11 matches as he gets ready for the U.S. Open, which starts Aug. 26 on hard courts similar to those used in Washington.
''I'm in a good rhythm and I'm serving well,'' said Isner, who has 49 aces and was broken only once in three matches this week. ''I'd like to think I can hold my serve no matter what's under my feet, but I do think this (surface) helps my serve.''
The 20th-ranked and eighth-seeded Isner, who won the hard-court title at Atlanta last week, will face unseeded Dmitry Tursunov of Russia for a berth in Sunday's final.
Earlier Friday, with the temperature reaching the high 80s, the 61st-ranked Tursunov overcame ...