Bernard Tomic of Australia defeated fourth-seeded Alexandr Dolgopolov 6-1, 7-5 from the Memphis Open on Thursday.
After easily winning the opening set with accurate serving, Tomic trailed 5-2 in the second set. At 5-3, the 23rd-ranked Dolgopolov failed to serve out the set. Tomic broke the 26-year-old Ukranian again for a 6-5 lead and held serve in the final game to move to his third quarterfinals of the year.
Also, Donald Young advanced with a 7-5, 6-3 victory over qualifier and fellow American Denis Kudla 7-5, 6-4. Steve Johnson of the United States was pushed to a third set tiebreaker by Dustin Brown of Germany before winning 4-6, 7-5, 7-6 (3).