In 2017, Williams played the Australian Open and won the title without dropping a set - and perhaps that might have been impressive enough, if not for the fact that at the time she was also two months pregnant with her now one-year-old daughter, Olympia. Last year, it was Keys who froze up in the final against Stephens in the tournament final.
American Madison Keys clinched her second consecutive U.S. Open semi-final berth on Wednesday, using her powerful serve and fiery forehand to get an edge on 30th seed Carla Suarez Navarro and win 6-4 6-3.
Osaka represents Japan and was born in Tokyo to a Japanese mother and Haitian father, but the family moved to NY when she was three before relocating to Florida five years later.
It was a routine start to the match in front of a relatively subdued crowd, still filling the stadium ahead of the men's quarterfinal between Novak Djokovic and John Millman.
That said, in Keys Osaka faces one of the few players capable of matching her blow for blow and not missing.
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Nishikori raced into a 4-1 lead but Cilic broke back to take the set to 4-4.
"I hate matches like this", said Tsurenko.
From diverse background, Naomi Osaka marches into forefront at U.S. Open
Open semifinals and the first to reach any Grand Slam semifinal since Kimiko Date did it in 1996 at Wimbledon. Osaka, whose father is Haitian, is the first Japanese woman since the start of the Open era to reach the U.S.
When asked during her media conference about Nishikori, Osaka said, "I don't know if I'm going to get in trouble if I say this". Osaka was tested for the first time by New Haven champion Aryna Sabalenka in the round of 16, but she won out 6-3 2-6 6-4 before hammering Lesia Tsurenko 6-1 6-1 in the quarterfinals. "I was freaking out inside, just like my whole body was shaking, so I'm really glad I was able to play well". That year, she beat already five-time Grand Slam victor Martina Hingis - the unstoppable World No 1, for her title - and summarily also took doubles honours with her sister Venus, the pair's second Grand Slam title.
She plays a semifinal against No. 19 seed Anastasija Sevastova of Latvia, who is appearing in the last four of a Grand Slam tournament for the first time.
For Osaka, her victory is the latest milestone in a watershed year for the 20-year-old who won her first WTA Tour title in Indian Wells, Calif., in March. That was at Wimbledon in 1995, and both Kimiko Date and Shuzo Matsuoka lost in that round.
But at her match this week, her response was subtle, but firm nevertheless - an appearance in a periwinkle, tulle tutu; the greatest, bar none.
Until Osaka's run this year, the best NY performance by a Japanese woman was 2004 when Shinobu Asagoe reached the quarterfinals.
"Unfortunately during this tournament I had many issues with my health, and today was not my day obviously".
It was another hot afternoon Wednesday, with temperatures in the high 80s but feeling about 10 degrees hotter with the humidity.
"That's a really big step for me, " Williams said.