The 22-time Grand Slam champion suffered a 6-4, 4-6, 6-4, 6-3 loss to an inspired Frances Tiafoe of the United States.

It was Nadal’s first defeat in a Grand Slam this year having triumphed at the Australian Open and French Open before pulling out of the Wimbledon semi-finals with an abdominal injury.

The 36-year-old’s heavily pregnant wife Mery Perello was admitted to hospital in Mallorca for an operation before the US Open got underway.

Speaking after his loss to Tiafoe, Nadal said he was unsure when he would play again as he looks to spend time with his wife.

"As you can imagine, right now it is difficult for me to make a clear analysis of what my immediate future is going to be," said Nadal.

"Right now what I have to do is go home, I have much more important things to attend to than tennis.

"It’s been a few months [that have been] a little difficult in every way, this is the reality.

"And from there, start again professionally speaking and , on a personal level, finish with something that is important in my life, which is having my first son and trust that everything will turn out well.

"I need to go back (home).

"I need to fix things, life, so I don't know when I'm going to come back.

"I'm going to try to be ready mentally.

"When I feel like I'm ready to compete again, I'll be there."

Nadal had won 22 matches in a row in this year’s Grand Slam tournaments before going down in four sets to Tiafoe, who has booked a quarter-final clash with Russian Andrey Rublev.

"I was not able to hold a high level of tennis for a long time," added Nadal.

"I was not quick enough on my movements.

"He was able to take the ball too many times very early, so I was not able to push him back.

"Tennis is a sport of position.

"You need to be very, very quick and very young.

"I am not in that moment anymore."