Pakistan, Aug. 23 -- Frances Tiafoe and Brandon Nakashima won quarterfinal matches Friday night to set up one all-American men's semifinal at the Cincinnati Open. Coco Gauff and Jessica Pegula also advanced to make it four U.S. players in the semis.

"It's insane, I think we're all doing so well," Gauff said. "Hopefully, you know, we can have a double title win. Obviously there are more matches to be played for that to happen. We definitely root for each other."

Tiafoe beat Italian Lorenzo Musetti, 7-6 (2), 7-5, and Nakashima beat fellow American Taylor Fritz, 7-6, 4-6, 6-3, marking the first time two Americans have reached the men's semifinals in Cincinnati since Andy Roddick and Mardy Fish in 2010. Nakashima is the first American man t...