Defending United Cup champions the United States reached the semi-finals of the competition after Coco Gauff won both her matches to clinch a 2-1 victory over Greece. 

Gauff, who was beaten in her last singles match by Spain's Jessica Bouzas Maneiro, got the USA off to a winning start on Wednesday with a 6-3 6-2 triumph over Maria Sakkari. 

However, Greece hauled themselves level thanks to Stefanos Tsitsipas, who got the better of world number nine Taylor Fritz with a 6-4 7-5 victory to make the tie go the distance. 

Gauff returned to the court to partner Christian Harrison for the mixed doubles, with the pair taking on Sakkari and Tsitsipas to see who would progress to the final four. 

And it was the USA who prevailed, with Gauff and Harrison clinching a 6-4 4-6 10-8 victory, setting up a tie with Iga Swiatek's Poland or hosts Australia. 

Switzerland also booked their place in the semi-finals, with Belinda Bencic continuing her unbeaten start at the tournament to help her nation to a 2-1 victory over Argentina. 

Bencic won her singles match with Solana Sierra 6-2 6-2 before Sebastian Baez levelled the tie after a 7-5 6-4 triumph over three-time grand slam winner Stan Wawrinka. 

But Bencic, along with Jakub Paul, helped Switzerland into the next round, with the pair earning a comfortable 6-3 6-3 win against Maria Lourdes Carle and Guido Andreozzi. 

Semifinals Secured

Team Switzerland reach the final four in Sydney. pic.twitter.com/A0ADRw4VsH

— United Cup (@UnitedCupTennis) January 7, 2026

Poland will take on Australia in the quarter-finals on January 9 after easing to a 3-0 win over the Netherlands, with Swiatek and Hubert Hurkacz doing the damage.

Swiatek downed Suzan Lamens in straight sets with a 6-3 6-2 victory after Hurkacz had edged a second-set tie-break to beat Tallon Griekspoor 6-3 7-6 (7-4) to seal the tie. 

Katarzyna Kawa and Jan Zielinski ensured a clean sweep for Poland in their final Group F game with a 6-3 3-6 10-4 triumph in the mixed doubles. 

Data Debrief: Gauff continues Sakkari dominance as Swiatek finds her groove

Gauff registered her sixth win against Sakkari, equalling her most wins against a single opponent at WTA level (also six victories against Aryna Sabalenka and Ons Jabeur).

Swiatek, meanwhile, now has a win rate of 87.5% in women's singles at the United Cup, the best of any player since the inception of the tournament in 2023 (over five matches played).