NEW YORK, USA - Naomi Osaka's title defense ended in the Round of 16 at the US Open to a familiar opponent, in No.12 Belinda Bencic, who has now won her last four matches over a reigning World No.1. 

Coming off an emotional win over 15-year-old Coco Gauff in the third round, Osaka struggled to into Bencic's service games and the Swiss star's game left her feeling rushed in the rallies and on her back foot for much of the match. 

After the match, Osaka told reporters this loss stung far less than her first-week exits at Roland Garros and Wimbledon over the summer, and she saw the tournament as a positive step forward in her level as the tour turns to Asia. 

"Right now I have this feeling of sadness, but I also feel like I have learned so much during this tournament," Osaka said. "Honestly, of course I wanted to defend this tournament.

"I feel like the steps that I have taken as a person have been much greater than I would imagine at this point. 

"So I hope that I can keep growing. I know that if I keep working hard, then of course I'll have better results."

"I mean, in Wimbledon I walked out on you guys," Osaka said, referring to a tearful end to her press conference after losing in the firsts round to Yulia Putintseva. "In Roland Garros, I came straight from the match, so I was all gross and I just wanted to get out of there.

"I feel like I'm more chill now. I feel like I grew. I don't feel like I put so much weight on one single match."

"Obviously, as you can see, I took a shower," she said with a laugh. "Yeah, I feel like I'm more chill now. I feel like I grew. I don't feel like I put so much weight on one single match."

"As a whole, I want to see that I played better matches through the summer. Because I feel like definitely the tournament that I played here has been the best one so far."

After going 0-2 during the grass season, Osaka rebounded well over the summer hardcourts. She made back-to-back quarterfinals in Toronto and Cincinnati, where she was forced to retire due to a knee injury. That injury continued to hamper her in the lead-up to the US Open and in Monday's match against Bencic. Osaka told Japanese reporters that she was not able to practice her serve as much as she would have liked going into the tournament, which led to its inconsistency. 

"Honestly, I'm not that mad at this," Osaka said. "Of course I can look at this and be very disappointed and mad, but I'm not mad at it. Of course I would like to reach higher, like, rounds. That's definitely what I'll aim for in Australia. 

"But for right now, I think the level of tennis that I was playing in Europe was not that great. Coming here: two quarterfinals, Round of 16. 

"Hopefully I'll do well in Japan because I always do well in Japan, and just keep building off of it to end the season."

In contrast to her last two major appearances, Osaka said this loss to Bencic left her even more motivated to get back on the court. 

"I feel actually better losing here than when I lost [to her] in Indian Wells, because, of course there's not a feeling of acceptance, but I feel like I learned a lot from today," Osaka said. "Like, there is a lot of things that I did wrong. 

"For me, whenever I do things wrong, I usually take it to the next match. That's when I play better. So honestly, I'm just excited for the next tournament."

"Hopefully I'll do well in Japan because I always do well in Japan, and just keep building off of it to end the season."

Osaka's next event will be a long-awaited return to her birthplace, the city of Osaka, Japan, which hosts this year's Toray Pan Pacific Open, a Premier event. Last season, Osaka followed up her US Open win by making the final on home soil. 

"To be honest, I'm not even thinking about playing tennis there right now," Osaka said. "All I'm thinking about is the takoyaki. I want to go to that street with the giant octopus sign, you know, the food street. I want to get some okonomiyaki. Honestly, I'm just there for the food."

"Yeah, it's definitely been a while since I've been to Osaka. So definitely super excited to go back there, and I hope that a lot of people come. I know that I'll have a lot of fun."

Earlier in the week, Osaka was asked to reflect on her last 12 months since winning her maiden major in New York, the lessons she's learned and the journey she's been on.

"I would describe it like a book," Osaka said then. "It's not quite done yet. But it's currently being written.

"I don't know how the ending is going to be. I only know what the chapters are. For me, I'm just reading it."

Asked on Monday for the title of the current chapter of that book, Osaka grew pensive. 

"This chapter is Chapter 5, and it's titled "The Process". Because it's a process."