Naomi Osaka is through to her first grand slam semi-final since returning from her maternity leave, beating Karolina Muchova to reach the last four of the US Open.

Osaka is through to the last four at Flushing Meadows for the third time after a 6-4 7-6 (7-3) victory over Muchova in one hour and 44 minutes on Wednesday.

The four-time major champion held firm at the start of the match, defending a break point in the opening game, though there was little to split the players after that.

Osaka then took her chance at 5-4, though, going 0-40 up before clinching the first set at the second time of asking.

Muchova had to have a medical timeout due to a problem with her left leg, but it did not affect her, as she got an early break, though Osaka hit straight back.

The Czech took the advantage again at 4-4, but Osaka once again dug deep, breaking to love in the following game before going to a tie-break, when she raced into a 4-1 lead and saw off the match.

She can make the whole place shimmer! @naomiosaka | #USOpen pic.twitter.com/4achL1yRqs

— wta (@WTA) September 4, 2025

"I'm really inspired by all the moms on tour," Osaka said after the match.

"But I also have this feeling like I'm not doing good enough or that I'm being left behind. And I think when all the moms came back, and they did well off the bat, I sort of felt like something was wrong with me.

"I know that Belinda [Bencic] made the semis of Wimbledon, so I just really felt like I was losing a race in some sort of weird way.

"So yeah, that was on my mind, but now I'm here, and I feel like a weight has been lifted off my shoulders."

Osaka will face Amanda Anisimova, who got her revenge on Iga Swiatek, in the semi-final, with her focus on reaching a first final since her Australian Open triumph in 2021.

Data Debrief: Osaka breaks familiar ground

When reaching the quarter-final of a grand slam, Osaka has never failed to get her hands on the trophy.

And she is just the fifth player in the Open Era to reach each of her first five women's singles semi-finals at major events on the same surface, along with Rosie Casals, Kerry Reid, Virginia Wade (grass) and Caroline Wozniacki (hard).

Among players who started their career in the Open Era, Osaka has become the third player to win each of her first five women's singles quarter-finals at grand slams after Chris Evert and Aryna Sabalenka.