Keys undone by debilitating nerves in shock US Open defeat

NEW YORK :Madison Keys said the nerves she experienced in her first U.S. Open appearance as a Grand Slam winner proved "paralysing" after the sixth-seeded American was sent spinning out of the opening round in New York on Monday.

Keys notched up a staggering 89 unforced errors and made 14 double faults in her 6-7(10) 7-6(3) 7-5 defeat by Mexican Renata Zarazua in front of stunned spectators on Arthur Ashe Stadium to become the highest seeded casualty of the women's draw so far.

It was a bitterly disappointing finish to a Grand Slam season that began with her maiden major title at the Australian Open in January and the 30-year-old said the jitters cost her dearly against her unseeded opponent.

"I feel like today ... for the first time in a while, my nerves really got the better of me, and it became a little bit paralysing," Keys told reporters.

"I felt like I was just slow, I wasn't seeing things the way that I wanted to which I feel resulted in a lot of bad decisions and lazy footwork.

"So I feel like that's the summary."

Three years ago, Keys spoke openly about the "dark pit of despair" that she was in when her career had stalled due to the suffocating pressure of trying to stay at the top level of the sport and she said expectations weighed heavily on her again.

"I think it was probably building a little bit," she added.

"You always feel first-round jitters and as the day gets closer, feel a little bit more and more nervous.

"But I feel for whatever reason today I couldn't separate myself from the ... feeling that winning matters just way too much ... Once you start playing badly it just all snowballs."

The 2017 U.S. Open runner-up suggested that the gruelling season had also taken a heavy toll.

"As the year has gone on and on