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The Spaniards, without world number one Carlos Alcaraz after he pulled out on the eve of the event with a hamstring injury, had their backs against the wall when Pablo Carreno Busta was beaten in straight sets by Jakub Mensik.

Carreno Busta, ranked 89th, had no response to Mensik's power and 20 aces, going down 7-5 6-4 to the world No. 19.

Mensik suffered a break midway through the first set but held tough and broke back twice to bag it. He gave away no other break opportunities, snatching the second set with a late break of his own to put his team in front.

Even without Alcaraz, Spain had enough quality to stage a successful comeback, with Jaume Munar drawing it level with a 6-3 6-4 win over Jiri Lehecka. Munar, who earned his first Davis Cup win, needed a break in each set to get past his opponent.

It then came down to the doubles match with 39 year-old veteran Marcel Granollers and Pedro Martinez edging past Mensik and Tomas Machac 7-6(8) 7-6(8) in an entertaining encounter.

Argentina's Tomas Etcheverry fired 23 aces to earn a straight-sets victory over Jan-Lennart Struff in the last quarter-final of the day, but the Germans responded with Alexander Zverev's 6-4 7-6(3) victory over Francisco Cerundolo to send the tie into yet another doubles decider.

There was drama in the decider that lasted almost two and a half hours. Argentina's Horacio Zeballos and Andres Molteni saved four match points but wasted two themselves in the third set tiebreak before Germany's Kevin Krawietz and Tim Puetz battled back to a 4-6 6-4 7-6(10) victory to send their team to the last four.

In the other semi-final, host Italy, also missing world number two Jannik Sinner and world number eight Lorenzo Musetti, is eyeing a Davis Cup "three-peat" after easing past Austria in Bologna to set up a semi-final clash against Belgium.