Tennis's biggest names have hit highs and lows down under over the weekend, with stars like Coco Gauff seeing mixed results at the 2026 United Cup as the annual Australian Open team tune-up tournament heads into its knockout rounds.

World No. 4 Coco Gauff and the reigning champion Team USA are through to the quarterfinals, joined by top WTA competitor and No. 11 Belinda Bencic of Team Switzerland.

Argentina, Australia, Belgium, Czechia, and Greece also punched their tickets to the knockouts, with Tuesday night's final group-stage bout deciding whether No. 2 Iga Świątek and Team Poland or Team Germany will claim the final spot in the quarterfinals.

Thus far in the team competition, however, Gauff has experienced a particularly up-and-down tournament, suffering her first-ever United Cup singles defeat on Monday against No. 42 Jessica Bouzas Maneiro of Spain after causing a stir with her postmatch comments.

"I feel like we're definitely, in tennis, the worst," she told reporters before the singles showdown. "I've always said I wish our country in other places would show up throughout the world as we see smaller countries support."

After taking some heat, the 21-year-old later clarified her position on social media, writing "Trust me I understand the financial aspect of things and know tennis is not accessible for everyone, it was more of a comment for those who are already attending and how I wish they were as passionate as those from other countries."

How to watch Gauff and Team USA at the 2026 United Cup

Gauff will look to return to form against No. 51 Maria Sakkari when Team USA kicks off the 2026 United Cup quarterfinals against Team Greece at 9 PM ET on Tuesday, airing live on the Tennis Channel.