The Spanish ace suffered a straight-sets loss to Botic van de Zandschulp in the second round in New York and simply felt that his opponent played a lot better than expected.

Alcaraz said: "I don't know what to say right now. First of all, I think he played great. He played really good tennis.

"I thought he was going to give me more points. I'm going to say more free points. He didn't make a lot of mistakes that I thought he was going to do.

"So I was confused a little bit. I didn't know how to manage that, how to deal with it. I couldn't increase my level.

"I think my level stayed at the same point all the match, and it wasn't enough to win the match or to give myself the chance to get into the match or try to give myself chances. So what can I say?"

Alcaraz suggested that a busy summer schedule - that saw him win Wimbledon before losing to Novak Djokovic in the Olympic final in Paris - may have contributed to his defeat although he didn't want to make excuses.

The world number three said: "I’ve been playing a lot of matches lately with Roland Garros, with Wimbledon, Olympic Games.

"I took a little break after the Olympic Games. I thought it was enough. It was really helpful for me. Probably it wasn't enough.

"But yeah, probably I came here with not as much energy as I thought that I was going to come. But, I mean, I don't want to put that as an excuse."