"It really means a lot", said Osaka whose post-match, on-court interview endeared her further to a growing legion of fans. Keys ability to hit winners even from deep in the court is one of her most impressive attributes and one that Osaka will need to be wary of.
It was just the latest in what's been a dominant run for Osaka.
Nishikori got the early break in the fifth set and led by 4-1 but Cilic got back on serve at 4-5.
However Nishikori fought back and took the next two sets before Cilic forced a decider.
But this US Open represents new and still uncharted territory for Williams, and nobody - least of all Serena - will say she's back until. she's back. I think she can win a title now. That was at Wimbledon in 1995, and both Shuzo Matsuoka and Kimiko Date lost in that round. I just needed one more match before playing a top 10.
It was a very comfortable afternoon for Osaka who became the first Japanese woman in 22 years to reach a Grand Slam semi-final. "I was freaking out inside, just like my whole body was shaking, so I'm really glad I was able to play well".
Samsung May Reveal a Foldable Smartphone This Year
He added that that development of the device has "nearly concluded", although warned that the process is "complicated". Samsung plans to launch the world's first foldable smartphone , likely to be called the Galaxy X , later this year.
Key's compatriot Serena Williams will match up against Anastajia Sevastova in Thursday's other semi, with the six-time champion looking to match Margaret Court's all-time record of 24 major wins - just a year after giving birth to her first child.
But at her match this week, her response was subtle, but firm nevertheless - an appearance in a periwinkle, tulle tutu; the greatest, bar none.
Cilic has made two grand slam finals since but Nishikori has never been back and will now take on either twice U.S. Open champion Novak Djokovic or unseeded Australian John Millman for a spot in Sunday's final.
So the Japanese are turning their attention almost 7,000 miles away, to the US Open and the USTA Billie Jean King National Tennis Center courts, to find some uplifting news.
Keys: 'I felt good today.
"I think power, obviously a big serve".
Tsurenko labored in the heat during her fourth-round victory over Marketa Vondrousova, having her temperature and blood checked during a medical timeout in the first set and almost quitting when she trailed early in the second. Osaka put it best after her quarterfinal win: "Sometimes I go insane and then I start hitting everything".
Osaka, who lived in her native Japan until she was 3, started playing tennis in NY after her father saw the Williams sisters playing at the French Open in 1999 and made a decision to teach his daughters.