The United States have won the inaugural United Cup after ice-cool go-to man Taylor Fritz gave Team USA an unassailable 3-0 lead over Italy in the best-of-five-rubber final in Sydney.

As he did in a similarly tight semi-final triumph over Hubert Hurkacz, Fritz held his nerve in the key moments to notch a 7-6 (7-4) 7-6 (10-8) victory over 2021 Wimbledon runner-up Matteo Berrettini on Sunday night.

The world No.9’s clutch win followed straight-sets singles wins also for Jessica Pegula and Frances Tiafoe.

“It’s amazing for the team to win this event,” Fritz said after being crash-tackled by Tiafoe amid wild celebrations.

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“We came in with really high hopes, or at least I did, for the event so I was really happy to be in that position to clinch the match.

“The emotions when you win and everyone comes running out here, it’s amazing.”

Pegula continued her hot summer to give the US a perfect start with a 6-4 6-2 victory over Martina Trevisan before Lorenzo Musetti retired injured after losing the first set 6-2 against Frances Tiafoe.

The back-to-back defeats left Berrettini needing to topple Fritz to keep alive Italy’s hopes at Ken Rosewall Arena.

He couldn’t as Fritz overcame the disappointment of failing to convert nine break points to nab both tiebreakers, as he did against Poland’s big-serving world No.10 Hurkacz on Saturday.

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Despite the dominant end scoreline of her match, world No.3 Pegula didn’t have it all her own way against the 27th-ranked Trevisan.

Trevisan, who took down world No.1 Maria Sakkari in Italy’s semi-final defeat of Greece, troubled Pegula in the opening set with her fearless power hitting.

Pegula, though, kept her cool and gained the fifth and final service break of the set to seize the ascendancy.

Reeling off seven straight games, Pegula skipped out to a 5-0 lead in the second set but the left-handed Trevisan rallied once more before Pegula closed out the match after 90 minutes.

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“Definitely very relieved,” Pegula said.

“First match of the day, first match of the final and Martina’s playing great.

“She’s a fighter, she’s competing and I feel like she’s thriving off the atmosphere here with the fans and her team and it’s really hard to beat someone like that.”

Highlighted by a stunning upset of world No.1 Iga Swiatek, Pegula has now won four straight singles matches at the new mixed teams’ event, plus four mixed doubles encounters in an impressive Australian Open build-up.

Tiafoe has been equally strong, with the 2022 US Open semi-finalist preserving his unbeaten record in the event with a fifth singles triumph to go with one mixed doubles win.

-AAP