US Open 2018: Naomi Osaka was willing to 'break a leg' to win
|2018 US Open|
|Venue: Flushing Meadows, New York Dates: 27 August-9 September Coverage: Live radio coverage on BBC Radio 5 live sports extra; live text commentaries on the BBC Sport website|
Naomi Osaka said she would have been prepared to "break a leg" to get every ball as she reached her first Grand Slam quarter-final at the US Open.
The 20th seed beat Belarusian Aryna Sabalenka 6-3 2-6 6-4 in New York and will next face Ukraine's world number 36 Lesia Tsurenko.
Japan's Osaka, 20, cried on court after her match and said she would "never have forgiven herself" had she lost.
Her compatriot Kei Nishikori is through to the men's quarter-finals.
"I was just thinking, 'I have to fight for every point; even if I break a leg I should try to get to every ball'," Osaka said.
She won the Indian Wells Masters tournament in March, beating world number one Simona Halep 6-3 6-0 in the semi-finals, and climbed into the top 20 in the world rankings.
Tsurenko overcame dizziness to beat unseeded Czech Marketa Vondrousova 6-7 (3-7) 7-5 6-2 to also reach her first Grand Slam quarter-final.
'That's a Pokemon quote, I'm sorry'
This was not the first time Osaka has made an impression with her post-match victory speech in the United States.
After winning the Indian Wells title, she made what she described as "the worst acceptance speech of all time" - nervously saying her 'thank yous' before awkwardly lifting the trophy and posing for photographs.
Two years ago, she was asked a question in a news conference about her career ambitions and responded by saying: "To be the very best, like no-one ever was."
Realising she had caused confusion, she added: "That's a Pokemon quote, I'm sorry. That's the Pokemon theme song. But, yeah, to be the very best, and go as far as I can go."
In January, Osaka apologised to the crowd after reaching the fourth round at the Australian Open by beating home favourite Ashleigh Barty.
"I feel really happy, but also kind of sorry because I know you guys really wanted her to win," Osaka said.
She has also told a 'knock, knock' joke on the BBC Radio 5 live tennis podcast.
Keys safely through to quarter-finals
Last year's runner-up Madison Keys is also through to the quarter-finals, beating 29th seed Dominika Cibulkova 6-1 6-3.
The American 14th seed broke twice in the first set and again on Cibulkova's first game in the second.
She dropped serve shortly afterwards but broke back twice to win in one hour and 16 minutes on Arthur Ashe.
Keys will face Spanish 30th seed Carla Suarez Navarro in the quarter-finals after she beat five-time Grand Slam champion Maria Sharapova.
She said: "I am glad I got the win and can come out here again for another match. It's always easier to be more energised when the person on the other side of the net is more energised than you can possibly be.
"She's a good player and has done a lot in her career. It was about having to focus on first serves and waiting for the right ball. I had to move my feet and used the crowd in those tight moments."
Ukraine's Tsurenko was close to collapsing because of heat exhaustion before recovering from a set and 2-0 down on the grandstand court.
"I was really dizzy and I asked nature or God or somebody please move the shade over faster," said the 29-year-old.
"I just thought, 'OK, I need just five minutes - keep fighting and I will feel better' and that's what happened. Now I need to rest and take an ice bath. I hate them but now I need it today."
Tsurenko knocked out world number two and Australian Open champion Caroline Wozniacki in the second round.