Brandon Nakashima continued his red-hot pace on Friday, knocking out sixth-seeded Taylor Fritz 7-6 (11/9), 4-6, 6-3 to reach the ATP-WTA Cincinnati Masters semifinals.
Unseeded Czech Sara Bejlek also advanced, backing up her stunning victory over world No 1 Aryna Sabalenka with a 3-6, 6-4, 7-6 (7/5) quarterfinal win over Madison Keys.
Bejlek, 20, booked a semifinal showdown with fourth-seeded American Coco Gauff, who powered to a 6-2, 6-2 victory over 10th-seeded Ukrainian Marta Kostyuk.
Nakashima lined up an all-American men's semi against Frances Tiafoe, who out-lasted Italian Lorenzo Musetti 7-6 (7/2) 7-5.
Nakashima began his post-Wimbledon hard court run with a Washington semifinal, which he lost to Fritz, a run to the final in the Montreal Masters and now his best showing at Cincinnati – all with the US Open start barely more than a week away.
Nakashima withstood 22 aces from Fritz – who also bashed 31 unforced errors.
Nakashima trailed by a break in the third set but broke back to knot it at 3-3 and broke again for a 5-3 lead, out-hitting the powerful Fritz and converting his first match point with a forehand winner.
"I've gotten a lot of confidence over the summer," Nakashima said. "In the final set I trusted my game, I'm proud with how I ended the match."
Tiafoe needed four match points to get past Musetti in a match played at a slow but intense pace.
"He's a hell of a player, he makes you beat him - and that's what I did," said Tiafoe, who was broken the first time he served for the match but won the next two games. "Each match is its own story. I just go out and compete as hard as I can."
BEJLEK KEEPS BELIEVING
Bejlek got off to a slow start against big-hitting Keys, a former Australian open champion and the 2019 winner in Cincinnati.
Bejlek trailed 0-3 on the way to dropping the first set but rode a wave of momentum shifts into the final four.
The Czech broke first in the third set only for Keys to battle back and force the tiebreaker, in which Bejlek rallied from 4-2 down on the way to a victory capped by a stinging winner down the line on match point.
"I just kept believing in the match no matter what," said Bejlek, who won her first WTA title in Abu Dhabi in February as a qualifier.
"I believed much more than ever, it was always in my head."
After a solid first set the 24th-ranked Keys broke in the third game of the second, but Bejlek, ranked 35th, broke back in the sixth and held for a 4-3 lead.
Keys answered with a love game, but Bejlek turned the tables two games later to force the third.
Two-time Grand Slam winner Gauff was dialed-in from the start against Kostyuk, breaking the 10th seed six times on the way to victory in 70 minutes.
Kostyuk, who had been 5-0 in quarterfinals this year, managed one break in each set, but they were minor hiccups for Gauff who lost just five points behind her first serve.
"Every match is getting better for me," Gauff said. "I'm being more decisive, my serve is improving and it is getting more and more rare for me to be broken."
She was expecting a challenge from the rising Bejlek.
"Sara is a great player," Gauff said. "I watched her win the title in Abu Dhabi. She's so athletic and fast, but she makes you earn every point."