Spanish tennis player Paula Badosa. AFP.
Badosa, ranked fourth in the world, twice recovered from a break down in the opening set as she booked a final-four showdown with seventh-seeded Daria Kasatkina, a 4-6, 7-5, 6-0 winner over fourth-seeded Aryna Sabalenka.
Gauff, the 18-year-old who reached her maiden Grand Slam final at the French Open this year, was coming off a lively victory over four-time Grand Slam champion Naomi Osaka on Thursday night.
The sixth-seeded American appeared to be riding the momentum from that win as she emerged from an exchange of three breaks of serve with a 3-2 lead in the opening set on the way to a 5-3 advantage.
After Badosa held serve, however, Gauff unravelled as she served for the set, firing three double faults to drop her serve as they went to tiebreaker, which Gauff surrendered with another pair of double faults.
She looked rattled as she dropped her opening service game of the second set, Badosa racing to a 5-1 lead and serving out the match with confidence two games later.
"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."
The Spaniard finished with 17 winners to 15 unforced errors, converting half of her eight break chances as Gauff's 29 unforced errors outpaced her 21 winners.
Badosa, who reached her fourth semi-final of 2022, will be taking on Kasatkina for the third time, with both prior meetings coming earlier this year.
Badosa beat Kasatkina in straight sets in Sydney in January, but Kasatkina triumphed in straight sets in the clay court tournament in Rome.
"She's winning a lot of matches, she's winning against the best players in the world, she's doing an amazing year," Badosa said.
Ninth-seeded Veronika Kudermetova maintained her perfect record against Tunisian Ons Jabeur, topping the third-seeded Wimbledon runner-up 7-6 (7/5), 6-2.
Kudermetova has won all three of her meetings against Jabeur in straight sets.
In their latest meeting, Kudermetova's 30 winners were almost double fifth-ranked Jabeur's 17. That included half a dozen aces.
Kudermetova will face Shelby Rogers, a 6-4, 6-4 winner over fellow American Amanda Anisimova.
Rogers, ranked 45th in the world, toppled world No. 3 Maria Sakkari, the top seed, in straight sets to reach the quarter-finals.
Rogers, who opened the tournament with a win over former US Open champion Bianca Andreescu, has yet to be broken this week and improved to 3-0 against Anisimova.
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