New York, Sep 4 : Naomi Osaka secured her spot in the U.S. Open semi-finals on Thursday with a hard-fought 6-4, 7-6(3) victory over Karolina Muchova, marking a powerful statement in her comeback to top-level tennis.

The four-time Grand Slam champion, seeded 23rd and returning to form after a long maternity break, maintained her perfect record in major quarter-finals, now standing at 5-0. This win sets up a high-stakes semi-final clash with Amanda Anisimova, as Osaka continues her impressive run at Flushing Meadows, four years after capturing her last major title.

"It means so much. I'm surprised I'm not crying," said Osaka.

"I was sitting up there watching and hoping I would have an opportunity to play on this court again, so my dreams are coming true... There's been so much hard work you guys haven't seen. I'm just grateful to my team. Hopefully you guys will come and watch my next round."

Muchova, who had spent over 10 grueling hours on court across her first four matches, took a medical timeout after narrowly losing the opening set, receiving treatment in the locker room for a suspected left leg issue.

Despite returning with her thigh heavily strapped, she came out aggressively and broke Osaka early in the second set. Though visibly hampered in her movement at times, Muchova continued to challenge Osaka with her crafty and unpredictable style of play, breaking to take a 5-4 lead. However, Osaka regained control just in time, forcing a tiebreak and ultimately sealing the match to advance.

"It was an incredibly difficult match. She is one of the best players in the world. Every time I play against her it's so difficult," Osaka said.

"Last year she beat me when I had one of my best outfits. I was really upset. I'm just grateful to be here."

/IANS