NEW YORK - Japanese number one Naomi Osaka reached her maiden Grand Slam semifinal as she overpowered unseeded Lesia Tsurenko from Ukraine in the US Open women's singles quarterfinal on Wednesday.

The No. 20 seed just needed 57 minutes to send her opponent packing 6-1, 6-1 and became the first Japanese woman to reach a Grand Slam semifinal since Kimiko Date at Wimbledon 1996.

Osaka said: "After I went into the quarters, I want to keep going, so I feel like I have to be focused and keep trying really hard."

The 20-year-old Osaka had total control over the match and was never really tested by Tsurenko. Osaka converted on five out of eight breaking points while Tsurenko had 31 unforced errors compared to just 11 from the Japanese.

Tsurenko said she was troubled by illness and was not able to play at her best in the match. "I just woke up today with a viral illness. I think my throat is not well. I'm not breathing well. I hate matches like this. I didn't want to show this kind of game in front of this big crowd, but unfortunately I'm just not able to play now."

The Japanese number one said she's mentally prepared for a deep run in a major.

"Now I don't feel pressure, so I feel a little bit like I'm used to it," she explained. "In Indian Wells I got a bit distracted if I'm in the lead. And now I feel like I'm finding it easier to try to close it up as quickly as I can."