"I didn't play that well," Osaka told reporters. "But honestly, I think at a time like this with that scoreline, I would usually feel very depressed and sad.
"But I feel pretty good right now because I think, given the circumstances, I tried my best and I don't really have any regrets."
Osaka, 21, said she lacked maturity when as a relative unknown player she won the tournament last year to kick off her meteoric rise through the rankings.
"One of the biggest things is I wanted to be more mature," she said when asked how she has changed in the past year.
"I feel like this is something I'm still working on, on and off the court. It's one of the biggest goals that I have had my entire life.
"Because I might have thrown a few tantrums last year and this year it's something I'm working on improving and I feel like it's going well."
The last year has been a whirlwind for the Japanese, who defeated her idol Serena Williams in the U.S. Open final in a match best remembered for the American's heated argument with the chair umpire as Osaka looked on.
After winning the Australian Open, Osaka shocked the tennis world by parting ways with her coach Sascha Bajin.
She lost in straight sets in her next match to Kristina Mladenovic at the Dubai Duty Free Tennis Championships, which left Osaka in tears.
But there were no tears on Tuesday as Osaka said she was adjusting to being the world number one and always having a target on her back.
"I feel like there is no anonymity," she said.
"That was something that I used to my advantage maybe when I was like 18, 19. But I think now there is way too many videos and too many people have watched my matches."
Despite the loss, Osaka is guaranteed to lead the rankings after the tournament since world number two Simona Halep also lost on Tuesday.
(Reporting by Rory Carroll; editing by Sudipto Ganguly)
