NEW YORK, NY, USA - It was getting late in the final set when No.20 seed Naomi Osaka decided that she didn't just want to win, she had to win.
Read more: Osaka - 'I fight with myself on court' through US Open success
"I had a lot of chances to break her in the third set," she recalled after a 6-3, 2-6, 6-4 win over Connecticut Open champion Aryna Sabalenka. "Then she would serve these really amazing serves. A part of me knew it was coming, but at the same time I was always very unprepared.
"I'm just real glad I was able to win in the end. I don't know. I was just thinking a little bit negatively of how I would feel if I lost or something."
Saying she wouldn't forgive herself had she lost during Monday afternoon's on-court interview, Osaka had been on the ropes at major tournaments before, having lost her last two US Open matches in heart-breaking three-setters to Madison Keys in 2016 and Kaia Kanepi last summer.
"There's people that call it 'a bad memory' here. Every time I play a Grand Slam, people ask me am I going to go farther than the third round. Then in Australia I went to the fourth round, then people were like, 'Are you going to go farther than that or is that where you're going to stop?'
"I've always dreamed of playing here and going to the quarterfinals and further. So I'm just glad I could do one of my goals."
After losing to Keys from 5-1 up in the third set, she shrugged off the concept of experience as an 18-year-old.
"Getting experience is good, but I feel like if you're a really good player it wouldn't really matter."
It took playing Sabalenka, who was playing her first Grand Slam fourth round after a stellar string of summer results at the Coupe Rogers, Western & Southern Open, and New Haven, for the Japanese youngster to see just how important experience really is.
"For once in my life, I actually think that I was the player with more experience, which is very odd for me to say," she confessed. "But I know that she just sort of recently started coming onto the Grand Slams and stuff.
"I don't know, I feel like there were moments that I kind of knew what to do. Maybe since she's so young..." she trailed off, perhaps realizing she and Sabalenka are currently the same age.
"She was a little bit hesitant. I feel like I learned a lot the match I played here two years ago, which people keep bringing up. I'm grateful that I had that experience."
The win on Louis Armstrong Stadium made a bit of history on Labor Day. Per WTA Stats and information, Osaka joined ATP star Kei Nishikori to make a Japanese man and woman into the quarterfinals of a Grand Slam since 1995.
"Seeing Kei do really well in Wimbledon, that really inspired me. I always thought if I can keep up with him, that would be really cool. I'm glad I was able to be a part of something like that today."
Calmly fielding questions in high-energy press room that featured questions in both English and Japanese, Osaka talked about everything from the match, whether matches should play let serves, and even how many friends she has off the court.
"What friends?" she self-depricatingly said to laughs from the press core.
"I literally only have, like, one friend that I'm actually completely myself with, and I feel bad for her sometimes! The other person is my sister, but I don't really count that as a 'friend.'
"I tell jokes a lot, but I'm not really that sure because sometimes people don't laugh and they just stare at me like I said something insulting."
After willing her way into a career-best Grand Slam result, Osaka will have another opportunity to knock 'em dead, on the court, and at the mic, taking on Lesia Tsurenko for a spot in the semifinals.
