The US reached the semi-finals of the United Cup mixed team tournament after beating Greece 2-1 in Perth on Wednesday, as Coco Gauff defeated Maria Sakkari before returning to clinch victory for the defending champions in the doubles.
Gauff, a two-times Grand Slam champion, beat Sakkari 6-3 6-2 in an hour and 26 minutes to put the US in front.
The 21-year-old had lost in three sets to world number 42 Jessica Bouzas Maneiro when the US took on Spain in Group A on Monday, but she shot out of the blocks against Sakkari and quickly racked up a 5-0 lead.
Sakkari showed some resistance, winning three straight games, but Gauff held serve to take the opening set before breaking the Greek twice in the second set to wrap up the win.
Greece's Stefanos Tsitsipas then earned a 6-4 7-5 win over world number nine Taylor Fritz to level the tie.
The 27-year-old was afforded little time to savor his first top 10 win since 2024, however, returning to the court just half an hour later alongside Sakkari to take on Gauff and Christian Harrison.
Momentum swung wildly in the hard-fought decider, with both teams taking a set apiece to send the match into a tiebreak.
The US raced into a 5-0 lead in the tiebreak, and though the Greek duo rallied to level at 6-6 a perfectly placed volley from Harrison squeezed through Tsitsipas's legs and sealed a 4-6 6-4 10-8 victory.
"I thought it was great level throughout, we just played free and aggressive," Gauff said.
Switzerland will face Argentina later on Wednesday.
The 18-nation event in Perth and Sydney serves as a warm-up for this month's Australian Open - the season's first Grand Slam.
