Coco Gauff and Christian Harrison continued their United Cup mixed doubles heroics in Perth Wednesday to lead the defending champion United States into the semifinals of the mixed teams’ tennis tournament.

Rallying from a set down against an inspired Stefanos Tsitsipas and Maria Sakkari, Gauff and Harrison won their third consecutive mixed doubles 4-6, 6-4, [10-8] to keep alive the country’s hopes of claiming a third United Cup title in the past four years.

United Cup: Scores | Standings

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 emerge victorious. The United States will now travel to Sydney to play the winner of the Poland-Australia quarterfinal. Today’s other quarter-final in Perth sees Switzerland play 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 responded with a 6-4, 7-5 triumph over World No. 9 Taylor Fritz to force the mixed doubles decider. Claiming his first top 10 win in more than 18 months, Tsitsipas, former World No. 3, rode a serving masterclass to a 6-4, 7-5 win.

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.

In fact, when Gauff is at her best, it’s not far-fetched to say the American puts the star in “stars and stripes.”

So, it came as no surprise that Gauff delivered in a moment as big as Wednesday’s. The World No. 4 defeated Sakkari 6-3, 6-2 in 1 hour and 26 minutes at RAC Arena, giving the United States the early lead. 

What made the performance even more impressive was that Gauff was coming off one of her rougher outings in recent memory, particularly on serve.

Those issues were nowhere to be found under the sunny Perth skies, as the 21-year-old led wire-to-wire.

“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.”

Highlights: Gauff defeats Sakkari to give USA lead vs. Greece in United Cup quarterfinal

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 semifinal tie, Gauff will either face Australia’s Maya Joint or Poland’s Iga Swiatek, withstanding the latter in last year’s United Cup final.