at the Union Buildings in Pretoria
Newport - Two-time champion John Isner and defending champ Nicolas Mahut eased into the quarter-finals at the ATP Tour's Hall of Fame Tennis Championships on Wednesday.
Two-time runner-up Lleyton Hewitt, of Australia, also advanced in emphatic fashion with a straight-set win in the grass-court tournament.
The top-seeded Isner hammered 11 aces in breezing past qualifier Austin Krajicek 6-3, 6-3 in just 63 minutes in Newport, in the United States.
“It was a pretty clean match,” said Isner. “I got an early lead on both sets and that helps so much. I play pretty well when I play (up a break).”
World number 12 Isner captured back-to-back titles at the event in 2011 and 2012, and is hungry for more.
Isner, who threw out the ceremonial first pitch at Tuesday's Boston Red Sox Major League Baseball game, will face fellow American Jack Sock in a quarter-final on Friday.
“Sock has an incredibly bright future,” said Isner. “He's got a lot of weapons in his game, especially with his forehand. He'll only get better.”
Former world No. 1 Hewitt humbled Croatian qualifier Ante Pavic 6-2, 6-2, while the fourth-seeded Frenchman Mahut rolled over Australia's Luke Saville 6-4, 6-2.
Mahut defeated two-time Grand Slam winner Hewitt in last year's Newport final, as Hewitt lost for the second consecutive year in the championship round. Mahut was also a runner-up seven years ago.
Hewitt next faces American Steve Johnson on Friday, while Mahut will play hard-serving Australian Samuel Groth on Thursday.
Second-seeded Croat Ivo Karlovic advanced by beating Ukrainian Sergiy Stakhovsky 7-5, 7-6 (7/3). Karlovic fired 18 aces to set up a date with Israeli Dudi Sela.
Groth outlasted Tunisian Malek Jaziri 7-6 (9/7), 7-6 (7/3).