US Open 2019: Coco Gauff learns valuable lesson in emotional defeat by world No 1 Naomi Osaka

Fifteen-year-old suffered a 6-3, 6-0 defeat in little more than an hour before both players broke down into tears and joined each other in the post-match interview

Coco Gauff's US Open came to an abrupt end under the bright lights of Arthur Ashe Stadium on Saturday but the 15-year-old said she would leave New York a better player after falling to world number one Naomi Osaka.

Backed by lively support from the packed home crowd, the young American was clearly overmatched against the defending champion, who needed just over an hour to book her ticket to the fourth round.

Osaka, 21, showed impressive sportsmanship by giving Gauff the opportunity to thank her fans in the post-match interview on the showcase court.

"It was amazing. I'm going to learn a lot from this match," a tearful Gauff said after the 6-3, 6-0 defeat.

"She's the number one player in the world right now, so I know what I need to do to get to that level.

"After the match, I think she just proved that she's a true athlete. For me, the definition of an athlete is someone who on the court treats you like your worst enemy but off the court can be your best friend.

"I think that's what she did tonight," added Gauff, who trained at the same Florida tennis centre as Osaka when they were younger.

Osaka said she had the idea to invite Gauff into the interview when they were shaking hands at the net.

"The thing that people don't see is that we go into the locker room and just cry and do press after," she said. "I thought it would be nice if she addressed the people who came and obviously cheered so hard for her.

"She's had an incredible week so I thought I'd just make a positive statement out of it.

"She told me I did amazing. She said would I do the interview, I said 'no I'm going to cry', but she encouraged me to do it.

"It was amazing, I'm going to learn a lot from this match. She's been so sweet to me."

Cori Gauff suffered a third-round defeat by Naomi Osaka at the US Open (Getty)

Osaka said that she did not feel like a mentor, but added: "I think this is the most focused I've been since the Australian Open. It was super fun. The energy was crazy, even if it really wasn't for me."

While she was full of compassion after the match Osaka was all business on the court, avoiding Gauff's dangerous backhand and taking advantage of her shaky serving on a warm night in Flushing Meadows.

Osaka predicted Gauff would become a threat to the game's top players when she builds some more power.

Gauff took the tennis world by storm at Wimbledon this year where she reached the fourth round and was given a wildcard to play at Flushing Meadows.

After a memorable battle in the second round with Tina Babos on Thursday Gauff was unable to make much inroads against Osaka's powerful serve, converting two of five break point opportunities and issuing seven double faults.

Gauff's U.S. Open is not quite over, as she will team up with Catherine McNally to take on Kveta Peschke and Nicole Melichar in the second round of the women's doubles on Sunday.

Osaka embraced Gauff and encouraged her to join her post-match interview (Getty)

For Osaka, a meeting with 13th seed Belinda Bencic awaits.

Twenty-one-year-old Osaka, back at the scene of her dramatic triumph against Serena Williams 12 months ago, handled the occasion far better.

A Gauff double fault in her first service game gave her opponent a break and set the tone for a display peppered with too many unforced errors.

A pair of aces eventually saw the younger player hold, and she then broke back before further breaks of serve were exchanged, Osaka finally holding to take the set.

At the start of the second, audible groans went around Ashe when Gauff's double fault brought up 0-30, and a second handed another break to Osaka.

Three break points in the next game briefly raised hopes of a revival, but they were quickly snuffed out by Osaka's booming groundstrokes.

It was all over when a Gauff forehand went long, and Osaka rushed to console the teenager.

Naomi Osaka believes she is playing the best tennis of her career so far (Getty)

Earlier, qualifier Taylor Townsend continued her remarkable US Open run with victory over Romanian Sorana Cirstea.

The American world number 116, who stunned Wimbledon champion Simona Halep in round three, beat Cirstea 7-5 6-2.

Townsend will face Canadian 15th seed Bianca Andreescu in the fourth round.

Andreescu defeated Caroline Wozniacki, the 19th seed, 6-4 6-4.

The 19-year-old Andreescu looks a real threat at Flushing Meadows this year and Wozniacki, twice a US Open runner-up, said: "She's playing very well and mixing up the pace. She has a lot of shots in her game that she can pull out.

"I think the one that I can most compare her game to would probably be Kim Clijsters, back in the day.

"I think because she moves well and she can stretch out and get to some balls and also play aggressive and using the angles.

"Everyone has their own style but for me, playing her, it a little bit brings me back to when I played Kim."

Germany's Julia Goerges pulled off a surprise by knocking out seventh seed Kiki Bertens.

Goerges, seeded 26, needed five match points but eventually got over the line 6-2 6-3.

American wild card Kim Ahn beat former French Open champion Jelena Ostapenko 6-3 7-5.

PA and Reuters