SYDNEY — Novak Djokovic and Iga Swiatek will headline the new-look United Cup mixed team event in Perth and Sydney from Dec. 29 to Jan. 7 as one of the key warm-up tournaments for the Australian Open.

Team Poland, led by world No. 2 and four-time Grand Slam champion Swiatek and Hubert Hurkacz, has been named as the top seed for the 2024 edition after the entries from the top 16 countries were released by Tennis Australia on Friday.

Stefanos Tsitsipas and Maria Sakkari will lead No.2-seeded Greece, with the defending champion United States, featuring Jessica Pegula and Taylor Fritz, seeded third. France, the No. 4 seed, will be led by Caroline Garcia and Adrian Mannarino.

Wimbledon champion Marketa Vondrousova will headline the Czech Republic team alongside Jiri Lehecka while Croatia rounds out the top six, featuring Borna Coric and Donna Vekic.

Four countries will make their debut in 2024.

Serbia, led by Djokovic and Olga Danilovic, and Canada, featuring Felix Auger-Aliassime and Leylah Fernandez, will compete for the first time. China’s Qinwen Zheng and Zhizhen Zhang and the Netherlands’ Tallon Griekspoor and Arantxa Rus will also make their debuts.

Other entries include Norway’s Casper Ruud, Germany’s Alexander Zverev and Angelique Kerber and Britain’s Cameron Norrie.

Each tie will consist of men’s singles, women’s singles and mixed doubles.

The Australian Open is scheduled for Melbourne Park from Jan. 14-28.