US Open 2019: Holder Naomi Osaka beats Coco Gauff to enter fourth round

Defending champion Naomi Osaka brought American teen Coco Gauff's captivating US Open run to a swift end with a 6-3, 6-0 win on Saturday to secure her spot in the fourth round.

World number one Osaka, who backed up last year's New York triumph with a win at the Australian Open but has since had an up-and-down season, simply overwhelmed her 15-year-old opponent in the marquee matchup under the Arthur Ashe Stadium lights.

"For me, I think this was the most focused I've been since Australia," Osaka said in an on-court interview, with Gauff standing beside her. "So, sorry for playing you with this type of mentality."

Gauff, who stunned the tennis world by reaching the fourth round at Wimbledon, committed seven double faults and was error-prone throughout the match.

Osaka set the tone early in the most hyped match of the tournament so far as the 21-year-old Japanese consolidated an early break for a 3-0 lead.

Gauff, in only her sixth Grand Slam match, then fired back-to-back aces to finally get on the board and from there the two exchanged breaks over the next four games before Osaka recovered from 0-30 to serve out the set.

Gauff, still unable to find any rhythm on her serve, made a pair of double faults en route to gifting Osaka a break to open the second set before the Japanese rallied back from 0-40 to consolidate for a 2-0 lead and then raced home from there.

At the end of the 65-minute match, Osaka approached an emotional Gauff at the side of the court, where the two embraced and spoke for a few minutes.

"She told me that I did amazing and good luck and then she asked if I could do the on-court interview with her and I said no because I knew I would cry the whole time but she encouraged me to do it," said Gauff.

"It was amazing. She did amazing and I am going to learn a lot from this match."

Up next for Osaka will be Swiss 13th seed Belinda Bencic, who beat Estonian Anett Kontaveit earlier on Saturday.