The US has won the inaugural United Cup after taking an unassailable 3-0 lead over Italy in the best-of-five-rubber final in Sydney.

American world number nine Taylor Fritz held his nerve in the key moments to notch up a 7-6 (7/4), 7-6 (10/8) victory over 2021 Wimbledon runner-up Matteo Berrettini at Ken Rosewall Arena.

Fritz’s clutch win followed straight-sets singles’ victories for teammates Jessica Pegula and Frances Tiafoe.

“It’s amazing for the team to win this event,” Fritz said.

“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.

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

Despite the dominant scoreline of her match, world number three Pegula did not have it all her own way against the 27th-ranked Trevisan.

Trevisan — who took down world number six Maria Sakkari in Italy’s semifinal 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 her American opponent closed out the match after 90 minutes.

Pegula won four straight singles matches at the mixed-teams event — highlighted by a stunning upset of world number one Iga Świątek — in an impressive Australian Open build-up.

AAP