Naomi Osaka was the first to book her spot in the last four, as she scored a 6-2, 6-2 win over Hsieh Su-wei in the morning session. Serena Williams then followed suit with a 6-3, 6-3 win over Simona Halep to set up Thursday's blockbuster showdown.
Noami Osaka has now won 19 matches in a row, a streak that dates back to last August and includes her second US Open title. So it comes as no surprise that Serena Williams is not taking her lightly.
"I have an incredible opponent to play, so it would be nice to hopefully keep raising the level of my game," Williams said. "I'm going to have to ... I feel like she does everything well. She has a good serve, she has a great return, she's strong on both sides."
The American, who is chasing Margaret Court's all-time record of 24 Major singles titles, also expressed happiness with her performance against Halep.
"Obviously I had to, going up against the No.2 in the world," Serena Williams added. "I knew I had to do better and that’s what I did. I’ve been watching her and I’m sure she’s been watching me."
Serena Williams credited her improved movement for her good run this fortnight, stating that it was something she had worked hard on during the off-season.
"I feel like this is such a good opportunity for me just to keep doing my best," the 39-year-old said. "It’s the first Grand Slam of the year for me. I had an incredibly long, arduous off-season. And so, I’m honestly happy with every win I get."
"Movement has always been one of my strengths, and so it's actually more natural for me to move than for me not," she added. "So it was just kind of like, 'Oh, that's how I used to move'. I'm happy that I'm doing that again and that I put it back into my game."
I feel really intimidated when I see Serena Williams on the other side of the court: Naomi Osaka
Earlier in the day, Naomi Osaka scored her fifth win in six career meetings against Hsieh, who is also the World No. 1 doubles player. The Japanese acknowledged the difficulty of playing an opponent as unconventional as Hsieh, but claimed she had complete clarity about what she needed to do.
"I feel like every time I play her, it's really challenging because I never know exactly what she's going to do with the ball," Naomi Osaka said. "I think today I just really focused on my game plan. I think it was kind of very clear what I thought I had to do."
Naomi Osaka leads the head-to-head against Serena Williams 2-1, but the 23-year-old admitted she still gets intimidated every time she faces off against the American.
"[Serena Williams is] someone that I feel really intimidated when I see her on the other side of the court," Osaka told the press, before the Williams-Halep match had been decided.