Stefanos Tsitsipas battled from a set down to topple Matteo Berrettini on Saturday but it was in vain as an unstoppable Lucia Bronzetti powered Italy into the final of the inaugural United Cup against a dominant United States. World number four Tsitsipas came through a do-or-die clash in Sydney 4-6, 7-6 (7/2), 6-4 to earn a crucial point for his country and boost his confidence ahead of the Australian Open.
But it wasn't enough with Bronzetti pummelling Greece's Valentini Grammatikopoulou 6-2, 6-3 in the following match to give Italy an unassailable 3-1 lead. They meet the United States in Sunday's final after the red-hot Americans swept past Poland 5-0.
Italy went into day two of the semi-finals with a 2-0 advantage after a gutsy Martina Trevisan upset world number six Maria Sakkari 6-3, 6-7 (4/7), 7-5 in a gripping encounter on Friday. Trevisan's teammate Lorenzo Musetti then crushed Greek teenager Stefanos Sakellaridis 6-1, 6-1.
With Tsitsipas winning, the pressure was on Grammatikopoulou, a late replacement for Despina Papamichail.
But she was outgunned by Bronzetti and reduced to tears in the first set.
"It's a special moment to bring such an important point to Italy. We are a great team, great friends and I'm so excited and so happy right now," said Bronzetti.
Berrettini, ranked 16, took a grip on his high-quality match with an unanswered break in game seven of the first set.
They went toe-to-toe in set two before the pumped-up Tsitsipas prevailed in a tiebreaker to take it to a third set where he ground down his tiring opponent.
Earlier, a composed Taylor Fritz beat Poland's Hubert Hurkacz in a battle of top 10 players to power the United States into the final.
The world number nine was too good for his big-serving opponent, ranked one place behind him, winning 7-6 (7/5), 7-6 (7/5).
Fritz came into the match with the United States already 2-0 up after Jessica Pegula stunned world number one Iga Swiatek 6-2, 6-2 on Friday and Frances Tiafoe swept past Kacper Zuk 6-3, 6-3. His victory gave them an insurmountable lead before Madison Keys made it 4-0 by beating Magda Linette 6-4, 6-2.