John McEnroe insists there is only one tennis star he would pay to watch play. As an iconic former player and a current broadcaster, the American rarely has to pay for his tickets to watch tennis matches.

McEnroe has been wowed by the likes of Carlos Alcaraz, Jannik Sinner, Novak Djokovic, Rafael Nadal and Roger Federer over the years. The developing rivalry between Alcaraz and Sinner has caught his attention, and he is a big fan of both players. A thrilling the world No. 1 in an epic five-set contest.

Despite both stars lighting up the ATP Tour, McEnroe insists he would only pay to watch Alcaraz.

"Not even in my wildest dreams would I have thought that Federer, Djokovic and Nadal would reach twenty Slams," McEnroe told . "Now you ask me if Sinner or Alcaraz can win 25. It seems crazy to me, but never say never.

"Modern tennis is in the hands of increasingly tall, violent, phenomenal athletes. I will disappoint you. I don't like to give numbers [on how many Grand Slams they might win]. If there is anyone who can surprise us, however, it is those two.

"Carlos is the most talented young man I have ever seen hold a racket, Jannik is not far behind. Alcaraz is brighter, Sinner is more consistent. I am struck by the sound of Jannik's ball. I have never heard anything like it. Carlos is the best gift the post-Big Three generation could give us. And he's the only tennis player I'd pay a ticket for."

McEnroe added that picking between Alcaraz and Sinner was like choosing between the Beatles and the Rolling Stones, the two biggest bands of his youth.

The seven-time Grand Slam champion continued: "It's like choosing between the Beatles and the [Rolling] Stones, who do you prefer? I loved Led Zeppelin. The Stones were unpredictable but sometimes the Beatles were better. We're talking about groups that, like Jannik and Carlos in tennis, have made history."

Alcaraz produced one of the greatest comebacks in tennis history to defeat Sinner at Roland Garros. Finding himself two sets down against the Italian, he won the third set before sealing a 4-6 6-7 6-4 7-6 7-6 victory.