The fourth edition of the United Cup, a combined ATP/WTA international team event, will get underway on Friday, launching the 2026 tennis season highlighted by Naomi Osaka’s maiden appearance at the competition.
With her sights on further glory, she will kickstart the new season at the United Cup for the first time this weekend.
Shintaro Mochizuki, Yasutaka Uchiyama, and Nao Hibino will join Osaka in Team Japan to battle against Greece and Great Britain in the group stage.
The seven-time titlist will open Group E action on Friday night against world No. 52 Maria Sakkari, representing Greece.
Last March, the 30-year-old, a two-time major semifinalist, defeated Osaka in straight sets at the Miami Open quarterfinals, their sole matchup of the 2025 season.
On Sunday, the Japanese player will take on a new challenge at the venue when she faces off against former US Open winner Emma Raducanu, who is also making her debut at RAC Arena in Perth, Australia.
Then, on January 7, the quarterfinals will take place; the winner of Group C will meet the winner of Group E in the night session.
Back to action after her pregnancy break, the former world No.1 built momentum throughout the second half of the year, finding the run of form that led her to rise in the rankings from world No.57 to No.16.
With a consistent campaign to the final at the Montreal WTA 1000, and a stellar semifinal run, her first since becoming a mother, at the US Open last September, the 28-year-old showed the tennis world impressive progress.
Earlier, the four-time major champion won her first title since 2021 at the WTA 125 in Saint-Malo, France, a confidence-boosting result ahead of the North American summer.
Moreover, by unleashing her trademark firepower, she earned notable victories against some of the best players on tour, including reigning Roland-Garros champion Coco Gauff.
World No. 3 Gauff will compete at the United Cup, helping her country defend the crown.
The encouraging results achieved by the Japanese player came when she started working alongside Iga Swiatek’s former coach, Tomasz Wiktorowski, last July.
United Cup 4.0
Across 10 days (January 2-11), the host cities of Perth and Sydney will welcome an 18-country line-up; each city serving as home for nine teams.
Team USA, Spain, Argentina (Group A), Italy, Switzerland, and France (Group C) complete the field based in Perth.
Meanwhile, in Sydney, the Ken Rosewall Arena will welcome Team Germany, Poland, the Netherlands, Canada, Belgium, China, Australia (host country), Czechia, and Norway.
According to the rules, the group stage matches will consist of three groups of three countries, competing round-robin style.
Each session will feature three matches: one men’s singles match, one women’s singles match, and one mixed doubles match. Both singles matches will feature the No. 1-ranked single player within the team.
Group winners in each city advance to the quarterfinals, with one quarterfinal spot in each city awarded to the best runner-up.
Sydney will also host two semifinals, followed by the United Cup Final on Sunday, 11, 2026.