Carlos Alcaraz admitted Wednesday it will be a “difficult moment” facing “idol” Rafael Nadal when the Spanish superstars clash for the final time. Nadal, the winner of 22 Grand Slam titles, announced last week that he will retire from tennis after the Davis Cup Finals in Malaga next month.

On Thursday, however, the 38-year-old will take on Alcaraz for a place in the final of the Six Kings Slam exhibition event in Riyadh. “Since I started to play tennis, I’m watching his matches. I look up to him and I grew up watching him. He was my idol, he is still my idol,” Alcaraz said on court after defeating Holger Rune 6-4, 6-2 to set-up an emotional meeting with Nadal.