Will the U.S. repeat at the 2026 United Cup? Czechia, Italy or Japan may have something to say

Twelve months ago, Coco Gauff and Taylor Fritz steered the United States to a second United Cup title in the event's first three editions without losing a match.

The American duo, along with Mackenzie McDonald, Nicole Melichar-Martinez, Varvara Lepchenko and Christian Harrison, is running it back in 2026, and are the odds-on favorites to repeat as the top seeds.

Read more: Swiatek, Gauff, Osaka, Auger-Aliassime, Zverev among 2026 United Cup entrants

While No. 2 seed Canada, and two-time finalist Poland, figure to also be in the mix, our first Best of Three preview of 2026's season-opener looks at a trio of teams that could play spoiler for the top seeds.

📲🖥️ Bookmark for 2026: Stream the United Cup on the Tennis Channel App!

Czechia

The Czechs' one semifinal appearance across the first three editions of the United Cup feels like an under-performance for a nation that has, historically, punched above its weight—in team events and otherwise. But 2026 might be the year they change that behind first-time participants Jakub Mensik and Barbora Krejcikova.

The 20-year-old Mensik came into his own in 2025, winning his first ATP Masters 1000 event in Miami, and all-court ace Krejcikova should logically excel in a format that gives equal weight to singles and mixed doubles.

While the newly-minted 30-year-old's health is a question mark, again, after she retired from two of her final three tournaments of 2025, a healthy Krejcikova has the game to take it to any of the top women in the field, from Gauff and Swiatek to Belinda Bencic and Naomi Osaka.

Seeded just No. 11 in the competition, the Czechs are in Group D alongside hosts Australia and Norway.

Italy

Seeded No. 3, the Italians are also looking to raise their first United Cup trophy, and it would be no surprise if their No. 1 players, Flavio Cobolli and Jasmine Paolini, lead them to glory.

Both players love to play for Il Tricolore, and were key cogs in Italy's dramatic Davis Cup and Billie Jean King Cup victories last season, respectively. And that X-factor could give them an edge in what may arguably be the toughest round-robin group to predict in the competition: Group C.

Read more: Flavio Cobolli’s shirt-shredding performance gave Italy another tennis hero

Joining Italy in the Perth-based group are France and Switzerland. The former team is anchored by surprise 2025 Roland Garros semifinalist Lois Boisson, who'll be eager to prove her staying power in her sophomore season, and late-season main character Arthur Rindeknech, while the latter has 2025's Comeback Player of the Year Bencic and Stan Wawrinka, who hopes to start his final season on tour with a bang.

Japan

Japan is the only country making its debut in the competition this year, and benefits from placement in a Group E that's anyone's game. Though its star power outside of first-time participant Osaka isn't as strong as some of the other teams in the event (it has just four players, and its ATP player is No. 92 Shintaro Mochizuki, the 2019 junior Wimbledon winner), it was drawn with Greece and Great Britain.

United Cup stalwart Greece again fields Maria Sakkari and Stefanos Tsitsipas, but both are coming off down 2025 seasons that saw them both tumble down the rankings: Tsitsipas to No. 34, and Sakkari to No. 52. Great Britain, meanwhile, suffered a pre-tournament blow when Jack Draper announced over the weekend that he'll miss the Australian swing as he continues to rehab bone bruising in his playing arm.

Billy Harris, the ATP No. 124, steps in in Draper's stead, and though 2021 US Open champion Emma Raducanu had a resurgence 2025 and returned to the Top 30, the projected women's match between Osaka and Raducanu scheduled for Jan. 4 could foretell a lot about what country advances.