Carlos Alcaraz leaned back, looked up and yelled in celebration.The Spaniard had just secured a spot in the semifinals of the APT Finals in his tournament debut, setting up a match against top-ranked Novak Djokovic.

Vamos, vamos,” Spanish for “Come on, come on,” Alcaraz shouted as he clenched his fists after beating Daniil Medvedev 6-4, 6-4 on Friday.

”It’s one of the most difficult challenges that I’m going to face, facing Novak in the ATP Finals, where he has won six times,” Alcaraz said. “Novak is Novak. He is the best player in the world right now. He’s lost just six matches this year, he’s unbelievable.”

Alcaraz and Djokovic have played each other four times and won two each. Djokovic won their most recent encounter in the final in Cincinnati in August, while Alcaraz beat the Serb in the Wimbledon final.

“I’m going to play my best tennis and enjoy it the same way I did the past few matches,” Alcaraz said. “I’m excited to face Novak.”