Taylor Fritz claimed the deciding victory as the United States stormed into an unassailable 3-0 lead over Italy in the United Cup final.

Jessica Pegula and Frances Tiafoe paved the way for Fritz to be the hero with their victories over Martina Trevisan and Lorenzo Musetti earlier in Sunday's final in Sydney.

While Musetti retired hurt while trailing 6-2, WTA world number three Pegula dispatched Trevisan in straight sets, carrying on the form that saw her defeat Iga Swiatek in the USA's semi-final win over Poland.

And Fritz ensured that the inaugural United Cup went his nation's way with a 7-6 (7-4) 7-6 (7-6) win over Matteo Berrettini, who clawed back the first championship point but was unable to prevent his opponent taking the second.

"It's great. It’s amazing for the team to win this event. We came in with really high hopes, or at least I did, for the event," said Fritz, who is ranked ninth in the world by the ATP after winning three titles in 2022.

"I was really happy to be in that position to clinch the match."

There were jubilant scenes as the USA team rushed to celebrate with Fritz, though Tiafoe was perhaps slightly overzealous.

"Just the emotions when you win and everyone comes running at you, it’s amazing," Fritz said. "I don’t know if you saw the replay but Frances basically headbutted me!"