Newport, RI - An all-American quarterfinal saw Jack Sock upset top-seeded John Isner, while two-time runner-up Lleyton Hewitt safely secured a berth in the semifinals at the Hall of Fame Tennis Championships.
The seventh-seeded Sock straight-setted the two-time Newport champion Isner 6-4, 7-6 (7-4), with Sock recording the only break of the match in the opening set.
This marks the 21-year-old Sock's first win in four tries against the 6- foot-10 world No. 12 Isner.
Meanwhile, the third-seeded former world No. 1 Hewitt handled sixth-seeded two-time NCAA singles champion Steve Johnson, of the United States, 6-4, 6-4 on the grounds of the International Tennis Hall of Fame.
Hewitt lost to France's Nicolas Mahut in last year's Newport final and gave way to Isner in the 2012 title tilt.
The 33-year-old two-time Grand Slam champion Hewitt's opponent on Saturday will be the talented Sock. The two have never met on court.
Saturday's other semi will pit second-seeded Croat Ivo Karlovic against upstart Aussie Samuel Groth, who were a pair of quarterfinal winners here on Thursday.
The 2014 Newport titlist will earn $81,500.