Frances Tiafoe has gained momentum in his bid for another Delray Beach Open with a three-set win over fellow American Bjorn Fratangelo to advance to the quarter-finals.
The eighth-seeded Tiafoe prevailed 6-4 3-6 6-1 to improve his career record at the event to 9-2.
Tiafoe won his first ATP Tour title as a 20-year-old wildcard at Delray Beach in 2018.
"I love playing here," Tiafoe said.
"I love South Florida. It's a good vibe."
Tiafoe won the final four games of the first set and dominated the final set.
He dropped only eight points on his first serve against Fratangelo.
'We've known each other for a long time," Tiafoe said.
"He's a tough opponent. It's never easy playing somebody you like."
Briton Cameron Norrie defeated French third seed Adrian Mannarino 6-2 7-5 to advance to a last-eight clash with Tiafoe.
Hubert Hurkacz reached the quarters with a comfortable 6-2 6-2 defeat of Colombian Daniel Elahi Galan.
Polish fourth seed Hurkacz will next play qualifier Roberto Quiroz of Ecuador, who eliminated Croatian veteran Ivo Karlovic 6-2 6-4.