This is Badosa’s fourth semifinal match this year.
Badosa scored nine straight points while Gauff struggled to make good serves.
“It’s never easy to start against such an aggressive player with a big serve,” Badosa said.
“I think I adapted pretty well in the end of the first set, and I played a pretty perfect tiebreak, so I’m really happy about that.”
She will next face Daria Kasatkina on Saturday. Kasatkina comes off a win against Aryna Sabalenka 4-6, 7-5, 6-0 in a match that lasted 2 hours and 23 minutes. The match was marked with 22 double-faults from Sabalenka who was dealing with an injury late in the match.
Shelby Rogers also advances to the semifinals after she defeated fellow American tennis player Amanda Anisimova 6-4, 6-2. Her head-to-head record with Anisimova is now at 3-0. She also has not lost a set in there three matches she was in this week.
Rogers is the last American player remaining in the Citi Open. Her win against Anisimova is her 21st win against another American.
Rogers will next match up with Veronika Kudermetova who had ousted World No.3 Ons Jabeur 7-6(5), 6-2 on Friday. Like Rogers against Anisimova, Kudermetova has a 3-0 record against the Wimbledon runner-up.
The match between Jabeur and Kudermetova lasted 1 hour and 4 minutes. She fired 30 winners, nearly doubling Jabeur’s offering of 17. Six of those winners were aces, Kudermetovas ace total for the year is now at 148.