At 4-4 and 15-15 in the third set, the 22-year-old had trouble at Rod Laver Arena in Melbourne. The star was treated for a cramp, and the semi-final against German Zverev then developed into something else.
Alcaraz, who no longer had the same mobility in the game, dropped the third and fourth sets. In the fifth, his muscles were in order again and the Spaniard raised his game to another level.
In the end, he won the final set 7–5, securing his first Australian Open final.
"I usually say that you have to believe in yourself, no matter what you're up against. I had a tough time in the third set. Physically it was one of the toughest matches I've played in my short career," Alcaraz said in the victory interview on Eurosport.
"But I've been in similar situations before, so I knew what I needed to do."
Carlos Alcaraz - who already has two French Open titles, two at Wimbledon and two at the US Open - won 6–4, 7–6, 6–7, 6–7 and 7–5.
If he wins the final, Carlos Alcaraz will become the youngest male player to win all Grand Slam tournaments.
"I'm most excited to be playing my first final here in Melbourne. It's something I've been chasing for a long time."
"It's been a good two weeks so far and I've been getting better all the time."
In Sunday's final, 24-time Grand Slam winner Novak Djokovic of Serbia awaits; he defeated reigning champion Jannik Sinner of Italy 3–2 in sets.
