Coco Gauff pulled off double duty to drag defending champions the United States into the United Cup semifinals on Wednesday while world number two Iga Swiatek did her bit for Poland.
Fourth-ranked Gauff, who suffered a surprise defeat last time out, put the United States on their way in their quarterfinal against Greece with a 6-3, 6-2 win over former world number three Maria Sakkari in Perth.
Stefanos Tsitsipas brought Greece level by defeating struggling Taylor Fritz 6-4, 7-5.
In the deciding mixed doubles, Gauff teamed up with Christian Harrison to battle past Tsitsipas and Sakkari 4-6, 6-4, 10-8.
A quarter final battle that had it all 📷🔥 pic.twitter.com/TxV7f4rYB9
— United Cup (@UnitedCupTennis) January 7, 2026
The 21-year-old Gauff struggled with her serve as she suffered her first-ever defeat at the United Cup on Monday when she was stunned by Spain's Jessica Bouzas Maneiro.
"Definitely a much better match today," Gauff said after making light work of Sakkari.
"Last match, I just tried to erase it. That's the beauty of this tournament.
"So definitely happy to give my team the lead today."
Six-time Grand Slam champion Swiatek beat 97th-ranked Suzan Lamens 6-3, 6-2 in the tie against the Netherlands in Sydney.
Always two steps ahead 🧠 pic.twitter.com/k1DuDnR6ZO
— United Cup (@UnitedCupTennis) January 7, 2026
Hubert Hurkacz, on his way back after being out for seven months following knee surgery, defeated Tallon Griekspoor 6-3, 7-6 (7/4) as Poland sealed their last-eight spot.
Poland will play hosts Australia, with the winner facing the United States for a place in Sunday's final.
In Perth, Switzerland'a Belinda Bencic beat Solana Sierra 6-2, 6-2 but a 7-5, 6-4 loss by Stan Wawrinka to Sebastian Baez sent the tie into a mixed doubles decider.
The Swiss finished off the win with Bencic and Jakub Paul clinching the winning point over Maria Lourdes Carle and Guido Andreozzi 6-3, 6-3.
From first ball to final point 🇨🇭👊
— United Cup (@UnitedCupTennis) January 7, 2026
How Team Switzerland sealed their place in the semifinals. pic.twitter.com/LP0cROWPpA
The mixed-team United Cup features 18 teams and serves as a build-up towards the Australian Open, which starts on January 18.