Atlanta - Marcos Baghdatis beat fifth-seeded Frances Tiafoe 7-5, 6-1 on Thursday in the BB&T Atlanta Open to set up a quarter-final match against fourth-seeded Matthew Ebden.
The 33-year-old Baghdatis, from Cyprus, has won two straight matches at Atlantic Station after losing seven of his previous eight.
"It's been a tough year," Baghdatis said. "But what happened, happened. Now I'm here and I'm in the quarter-finals. I'm happy."
Ebden, from Australia, beat local favourite Donald Young 6-4, 6-4.
"I knew he was going to be tough here, because he lives here," Ebden said. "He practices in these conditions and he's as comfortable as anyone in these conditions, I suppose."
Baghdatis lost the 2015 final to John Isner, the 6-foot-10 former University of Georgia star who reached the quarterfinals Wednesday night in his bid to win the event for the fifth time.
Second-seeded Nick Kyrgios of Australia, the winner over Isner in the 2016 final, advanced to face Britain's Cameron Norrie.
Kyrgios beat Noah Rubin 7-5, 6-2.
"I always feel comfortable playing here," Kyrgios said. "Obviously, had a fair bit of success here. I just feel comfortable. The court suits my game style. I can serve well, I can make a couple of returns and play aggressively."
Norrie, the left-hander who starred at Texas Christian, topped Jeremy Chardy of France 5-7, 6-4, 6-4.
In the other quarter-finals on Friday, Isner will face seventh-seeded Mischa Zverev of Germany, and eighth-seeded Ryan Harrison, the losing finalist last year, will meet Chung Hyeon.
Results from ATP Atlanta men's tennis tournament on Thursday (x denotes seed):
Matthew Ebden (AUS x4) bt Donald Young (USA) 6-4, 6-4
Marcos Baghdatis (CYP) bt Frances Tiafoe (USA x5) 7-5, 6-1
Cameron Norrie (GBR) bt Jérémy Chardy (FRA x6) 5-7, 6-4, 6-4
Nick Kyrgios (AUS x2) bt Noah Rubin (USA) 7-5, 6-2