Gauff, Harrison win mixed-doubles thriller to send U.S. into United Cup semifinals

Coco Gauff and Christian Harrison extended their mixed-doubles success Wednesday in Perth, lifting the defending champion United States into the United Cup semifinals.

Rallying from a set down against Stefanos Tsitsipas and Maria Sakkari, Gauff and Harrison won their third straight mixed-doubles match, 4-6, 6-4, [10-8], to keep alive the Americans’ bid for a third United Cup title in four years.

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After trailing 6-1 in the 10-point match tiebreak, Sakkari and Tsitsipas rallied to level at 6-6, but the top-seeded Americans won four of the next six points to close out the victory. The United States will now travel to Sydney to face the winner of the Poland–Australia quarterfinal. In Wednesday’s other quarterfinal in Perth, Switzerland meets Argentina.

In a rollercoaster quarterfinal, Gauff gave the Americans an early lead with a 6-3, 6-2 win over Sakkari, marking Gauff's third straight win over Sakkari on the WTA Tour Driven by Mercedes-Benz.

But Tsitsipas answered with a 6-4, 7-5 victory over world No. 9 Taylor Fritz to force the mixed-doubles decider. The former world No. 3 earned his first Top 10 win in more than 18 months, using a dominant serving performance to close out the straight-sets result.

Putting 84% of first serves into play in the opening set pushed Tsitsipas into an aggressive mindset. He fired an ace to fight off a set point at 4-5 in the second set and broke Fritz in the following game to set himself up to serve out the match.

Tsitsipas improved to 9-2 at the United Cup in singles. It was his first Top 10 victory since defeating No. 5 Alexander Zverev, No. 2 Jannik Sinner and No. 10 Casper Ruud on his way to winning the 2024 Rolex Monte-Carlo Masters title.

But the vintage performance by Tsitsipas wasn't the only example of a top player showing their worth on the biggest stage Wednesday.

Gauff delivered when it mattered most Wednesday, securing a composed 6-3, 6-2 victory over Sakkari in 1 hour, 26 minutes at RAC Arena to give the United States an early lead.

The performance came just days after one of her more uneven recent outings, particularly on serve, but any lingering concerns quickly faded. The World No. 4 was in control from the opening games, dictating play throughout and never allowing Sakkari to establish momentum.

"I think for me [the loss to Bouzas Maneiro] felt like one of my worst matches of my career," Gauff said Wednesday. "I felt like I was practicing well, and I'm playing practice sets well, and my first match went well. So I tried to erase it and learn from it.

"I don't think I was the most positive that match, so I just tried to stay positive regardless of what happened today."

Gauff posted much-improved numbers from the service line, landing 68% of her first serves while winning 76% of those points. After hitting 14 double faults just two days earlier, she cut that total to six against Sakkari en route to her 245th career victory.

For Sakkari, the match was a step back in what has otherwise been a promising week, highlighted by wins over Naomi Osaka and Emma Raducanu. While the season is young, 2026 looms large for the 30-year-old. A former top 5 player, Sakkari enters the is currently No. 52 in PIF WTA Rankings.

The win marked Gauff’s third straight over Sakkari and gives her a 6-5 edge in their head-to-head.

In the semifinals, Gauff will meet either Australia’s Maya Joint or Poland’s Iga Swiatek, whom she defeated in last year’s United Cup final.