World number one Jannik Sinner helped defending champions Italy come from behind to beat Argentina and book a place in the semi-finals of the Davis Cup.
After indoor hardcourt specialist Francisco Cerundolo had defeated Lorenzo Musetti in straight sets, Sinner wasted little time in levelling the tie with a convincing 6-2 6-1 win over Sebastian Baez.
In the deciding doubles showdown at Malaga's Martin Carpena Arena, Italy captain Filippo Volandri then opted for a line-up change as Sinner returned to pair with Matteo Berrettini against Maximo Gonzalez and Andres Molteni.
The inspired tactical switch saw the Italians take the opening set 6-4, with Sinner and Berrettini then earning a key break in the 11th game of the second before closing out victory 7-5 on a first match point to secure a place in the semi-finals against Australia, last year's runners-up.
Australian Open and US Open champion Sinner had last week won a first ATP Finals title to delight home fans in Turin, cementing his place at the top of the men's game, but was quick to pay tribute to his Italy team-mates for a collective effort in Malaga.
"He played unbelievable today, Matteo," Sinner said in his courtside interview. "You know he carried me today, so I am very happy about his performance."
Speaking earlier after his singles victory, Sinner said on Tennis Channel: "The court is very fast and tough to play. I haven't had so much time to adapt to these conditions, but the most important thing was to keep Italy alive.
"The last part of the year is very tough. It is nice to have your team-mates who push you through this in the last step of the season."
The opening singles match had seen Cerundolo, the world No 30, defeat Lorenzo Musetti 6-4 6-1. Both players had struggled to hold serve early on, with five breaks in the first set.
Cerundolo, though, broke Musetti in the opening game of the second set and then twice again to close out victory in just over an hour and a half.
Bryan defends doubles line-up as United States beaten by Australia
Australia had reached the semi-finals with a hard-fought 2-1 victory over the United States, whose late doubles gamble backfired.
Thanasi Kokkinakis gave Australia the ideal start with a 6-1 4-6 7-6 (14) victory over Ben Shelton in the opening singles, the world number 77 saving four match points before converting his seventh in an epic tie-break.
Taylor Fritz made light work of beating Alex de Minaur 6-3 6-4 to level the tie before Matthew Ebden and Jordan Thompson defeated Shelton and Tommy Paul in the decisive doubles.
Paul and Shelton were late replacements for doubles specialists Austin Krajicek and Rajeev Ram but their lack of experience told in a 6-4 6-4 loss.
"It was a match-up decision in this case, and I wouldn't change a thing," United States captain Bob Bryan told reporters. "We were hoping to catch the Aussies a little bit by surprise, but those guys rose to the occasion and served a high percentage, took care of their shots and stepped up..
"Ben [Shelton] was obviously on the court for three hours earlier in the day, you find rhythm out there. Tommy, you saw what he did at the Olympics. We took a shot at it. As a captain you have to make tough decisions. This wasn't a black-and-white decision. It was razor-thin edge and we went with it."
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