United Cup 2025: Dates, format, lineup and everything you need to know

Four of the Hologic WTA Tour's Top 6 will open their 2025 seasons at the United Cup, a nation-based competition that will see stars of the ATP and WTA compete side-by-side across two host cities in Australia.
World No.2 Iga Swiatek
Here's what you need to know about the United Cup:
When is the tournament?
The United Cup is an 18-team, mixed-team competition. The 10-day tournament begins on Dec. 27 and will be played across two cities, Sydney (Sydney Olympic Park Tennis Centre) and Perth (RAC Arena).
Perth’s RAC Arena will host the first day of the United Cup on Friday, Dec. 27, with the group stage in Sydney beginning on Saturday, Dec. 28.
Teams in Sydney will play on outdoor hard courts. Perth will feature an indoor hard court. Both venues will use the Dunlop Australian Open balls.
What is the format?
Each city will host three groups of three countries for a total of nine teams, competing in a round-robin format. Ties are comprised of one men's singles match, one women's singles match and one mixed doubles match.
Singles matches are best-of-three tiebreak sets. Mixed doubles matches are two tiebreak sets with a deciding match tiebreak (10 points) at one set-all.
Each group winner in each city will advance to the quarterfinals, with one quarterfinal spot in each city awarded to the best runner-up from that city.
Quarterfinal winners progress to the semifinals and finals, both hosted in Sydney. Teams advancing from Perth will receive a travel day and rest day on Jan. 2 and 3.
The semifinals will be played on Saturday, Jan. 4 and the final will be played on Sunday, Jan. 5.
How have the groups been drawn?
The groups were drawn in October. Here's where each of the 18 teams will play:
Perth
Group A: [1] United States, Canada, Croatia
Group C: [3] Greece, Kazakhstan, Spain
Group E: [5] China, Germany, Brazil
Sydney
Group B: [2] Poland, Czech Republic, Norway
Group D: [4] Italy, France, Switzerland
Group F: [6] Great Britain, Australia, Argentina
For a full breakdown of the draw and participants, click here. World No.5 Zheng Qinwen has withdrawn from the event.
Previous champions
The United States, led by Jessica Pegula
What is the prize money and rankings points on offer?
The total prize money pool for the United Cup is a minimum of $10,250,000, split equally between the ATP and WTA. Individual prize money is based on ranking, match wins and team wins. No points will be awarded for mixed doubles.
A player can earn a maximum of 500 points for the week, depending on their ranking.
Notable storylines
Rybakina rings in the new season: The first match of the Hologic WTA Tour season will be played in Perth on Dec.27 and World No.6 Elena Rybakina
Swiatek and Muchova set to clash on New Year's Day: World No.2 Iga Swiatek
Gauff changes things up: After sweeping the Auckland title in her last two seasons, World No.3 Coco Gauff
Italy eyes continued domination: The Azurri finished 2024 by sweeping the titles at the Davis Cup and the Billie Kean King Cup and their depth has them well-positioned to win a third straight team competition. World No.4 Jasmine Paolini
Bencic returns from maternity leave: Former No.4 Belinda Bencic
What else is happening in Week 1?
While the United Cup gets a jump start on the 2025 season, the WTA Tour will also see a flurry of action in Brisbane and Auckland.
World No.1 Aryna Sabalenka
At the ASB Classic in Auckland, New Zealand, Madison Keys