SYDNEY: Frances Tiafoe and Jessica Pegula delivered powerhouse performances to put the United States on the verge of clinching the inaugural United Cup against Italy on Sunday.

World number three Pegula, who burst into the top 10 in 2022 by winning the WTA 1000 Guadalajara tournament, stormed home 6-4, 6-2 against Martina Trevisan in Sydney.

Tiafoe then surged through the first set 6-2 against Lorenzo Musetti before the Italian retired due to a right shoulder injury.

“Definitely very relieved, first match of the day, first match of the final,” said Pegula.

“Martina is playing great, she’s a fighter, I feel like she’s thriving on the atmosphere with the fans and her team and really hard to beat someone like that.

“Glad I was able to play well enough to get the win.”

Tsitsipas outguns Berrettini to keep Greek United Cup final hopes alive

Taylor Fritz faces Matteo Berrettini next where victory for the American would seal the title in the best-of-five tie. Madison Keys is later due to face Lucia Bronzetti before a deciding mixed doubles rubber, if needed.

A dominant United States crushed the Iga Swiatek-led Poland 5-0 to make the decider of the mixed teams tournament – which began with 18 nations – while Italy outgunned Stefanos Tsitsipas’s Greece 4-1.

Trevisan stunned world number six Maria Sakkari in a gripping three-hour encounter on Friday, and her confidence was high.

But Pegula was also in red-hot form, toppling world number one Swiatek for the first time in the semi-finals.

She came out firing against Trevisan, racing to a 3-0 lead after breaking the Italian’s opening serve.

Trevisan showed the fighting qualities that helped her beat Sakkari to claw back, converting a break point in the fifth game and holding serve to get it back on level terms.

They exchanged breaks again on the fast hard courts before Pegula pounced once more to clinch the set on the Trevisan serve with a backhand winner.

It was all Pegula in the second as she put her foot to the floor, racing 5-0 clear.

But the Italian refused to give up and broke back as the American served for the match before her comeback faltered.

Tiafoe picked up where Pegula left off, breaking Musetti’s serve early, saving all three break points he faced.

The Italian increasingly touched his right shoulder as the set wore on before receiving treatment and calling it a day at end of the set.

“I thought it was a really high level … obviously at the end there I could see he was touching his shoulder a lot,” said Tiafoe.

“I didn’t want to win this way. I hope Lorenzo feels better.”