MALAGA - World number one Jannik Sinner triumphed in singles and doubles to help Davis Cup holders Italy beat Argentina 2-1 on Thursday to reach the semi-finals.
Italy will face Australia after they earlier defeated record 32-time winners the United States with a tense 2-1 victory.
Sinner won his first two Grand Slams this season, as well as triumphing at the ATP Finals last week without dropping a set, and blew Sebastian Baez away 6-2, 6-1 after Francisco Cerundolo comfortably beat Lorenzo Musetti 6-4, 6-1 in the opening rubber.
In the decisive doubles battle, Sinner and Matteo Berrettini shaded Andres Molteni and Maximo Gonzalez 6-4, 7-5 to progress.
"If they put me on the court in doubles I try my best," said Sinner.
"Matteo played unbelievable today, he carried me."
Italy booked a third consecutive return to the semi-finals and are favourites to win the Davis Cup for a second year running, in no small part because of Sinner's presence.
The 23-year-old is still waiting for the outcome of the World Anti-Doping Agency's appeal against his initial exoneration for twice testing positive for traces of the steroid clostebol in March.
Sinner beat Novak Djokovic in singles and doubles in last year's semi-finals on the way to helping Italy end a 47-year wait to lift the trophy again.
"I didn't have time to adapt to this court (after the ATP Finals) so I'm very happy with how I handled the situation today," Sinner told reporters.
"It was a very good doubles (pairing), he played unbelievable, I tried to stay there (with Berrettini), he also gave me a lot of confidence to play."
The doubles teams were tied until the ninth game of the first set when Sinner won three points and then Molteni clipped his passing shot which was heading wide to hand Italy the decisive solitary break.
The second set was even tighter with Italy breaking for a 6-5 lead and sealing their victory with a Sinner smash.
Berrettini more than held his own alongside Sinner.
"When you're playing with Jannik the pressure is off a little bit, he's going to play great," said the world number 35.
Argentina's captain Guillermo Coria said he was pleased with his team taking Italy to the wire.
"It speaks of the respect Italy have for us, and my doubles pairing, that they put the world number one out there," he said.
"We were close to taking out a powerful team like Italy."