Rafael Nadal and Iga Swiatek will participate in the United Cup 2023 event in Australia

Rafael Nadal and Iga Swiatek will kick off their seasons at the United Cup 2023 in Australia. The United Cup, with US$15 million in prize money and rankings points at stake, has replaced the men's ATP Cup as a key build-up to the Australian Open Grand Slam. It will be held in Brisbane, Perth, and Sydney.

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The first edition of the United Cup, the annual mixed team tennis tournament, will start on December 29, culminating on January 8. "The playing group is very excited about the United Cup. And that's confirmed in the high quality and calibre of those who've committed to the event. We are delighted with the depth and breadth of the teams. And we can look forward to many exciting matchups and lots of entertaining tennis." tournament director Stephen Farrow said Thursday.

Entries from the top 16 nations include Team Greece, Stefanos Tsitsipas, and female tennis player Maria Sakkari.

Number two-seeded Poland will be led by world No. 1 Iga Świątek and Hubert Hurkacz. While the third-seeded United States includes Jessica Pegula, Taylor Fritz, Madison Keys, and No. 19 Frances Tiafoe. On the other hand, emerging tennis powerhouses Italy will feature world number 16 Matteo Berrettini and Martina Trevisan. While the famed Rafael Nadal and world number 13 Paula Badosa will represent Spain.

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Meanwhile, Nick Kyrgios, Ajla Tomljanovic, and Alex de Minaur will represent the Australian team. Along with Czech Republic's Petra Kvitova, other star players include Norway's Casper Ruud, Germany's Alexander Zverev, Switzerland's Belinda Bencic, and Stan Wawrinka.

Brisbane, Perth and Sydney will each host two groups of three countries in a round-robin format from December 29 to January 4 with ties comprising two men's and two women's singles matches and one mixed doubles. Group winners of United Cup 2023 in each city will play off for one of three semi-final spots in Sydney, with the next best-performing team from the group stages joining them.