By Steve Keating

NEW YORK (Reuters) - American eighth seed Madison Keys claimed a dramatic 7-5 4-6 7-6(3) comeback win over a tearful Naomi Osaka on Friday to reach the fourth round of the U.S. Open.

Leading 5-1 in the third set and on the cusp of the biggest victory of her career, Osaka crumbled as Keys swept the next five games en route to a victory that left her stunned 18-year-old opponent fighting back tears.

"Those aren't the most fun matches but I just knew that if I stayed in the match that I could maybe have a chance to come back and get back in it," said Keys, who will next meet former world number one and U.S. Open finalist Caroline Wozniacki.

"Once I was able to get a little bit of momentum, I felt like I found my game a bit more. At that point, I knew I had to kind of step up or else I was going to be going home."

It was an excruciating collapse by her opponent played out on the game's biggest stage.

The Japanese world number 81 was left in tears several times as her lead slowly slipped away, a distraught Osaka at one point hanging her head and covering her eyes as she walked to a corner of the court.

But there was no place to hide inside the massive Arthur Ashe Stadium from the gaze of thousands of fans or a ruthless Keys, who moved in for the kill and clinched the comeback when Osaka sent a return wide.


Osaka's meltdown was in many ways reminiscent of a distraught Martina Hingis' 1999 collapse to Steffi Graf on center court at Roland Garros and Jana Novotna's tearful loss to Graf in the 1993 Wimbledon final when the Czech sobbed on the shoulder of the Duchess of Kent.

"At the end of the match, it kind of came down to experience, being in that situation before, having lost some tough matches," said Keys. "It happens. It just makes you stronger.

"You kind of just put it in the back of your mind and use it to fuel yourself and get back out there and try to get better."

It was not the first time in this U.S. Open fortnight that Keys has needed to pull off a great escape.

The 21-year-old American has made an adventurous start to the year's final grand slam, rallying from a set and a break down in her opening match to see off Germany's Alison Riske in a three-set nailbiter.

Keys was again forced to go the distance and a bit more by Osaka, who was making her first appearance in the U.S. Open main draw but made a solid start to her grand slam career by reaching the third round of the Australian and French Opens this year.

Osaka came out swinging freely from the baseline like a player with nothing lose but when the teenager suddenly looked up at the scoreboard as she lead 5-1 in the third set, the weight of reality dropped upon her.

With each missed shot, each missed opportunity, her nerves frayed a little more.

Twice Osaka would serve for the match and twice she would be broken.

"I think some losses are tougher than others," said Keys. "Some kind of stick around longer than others.

"But at the end of the day, if you can learn something from it, then you can take it as a positive."

(Editing by Frank Pingue and Mark Lamport-Stokes)