Serena Williams is taking nothing for granted as she heads into the US Open semifinals on Thursday with a record-equalling 24th Grand Slam title on the horizon.

“I'd been a couple of steps away at the last Grand Slam, so I'm definitely not ahead of myself,” said Williams, who fell to Angelique Kerber in the Wimbledon final in July.

“I still know that no matter whether I'm in the semifinals or the finals, I have a really long way to go to win that.

“That proved to be true at Wimbledon. I'm just taking it one at a time - literally.”

Williams booked her last-four spot with a 6-4, 6-3 victory over eighth-seeded Czech Karolina Pliskova.

The win came in her 100th match on Arthur Ashe Stadium, where she won the first of her six US Open titles in 1999.

She avenged a semifinal loss to Pliskova in the 2016 US Open and notched her first win over a top-10 player since she returned in March after the birth of daughter Olympia in September of last year.

“Shocking, my first top-10 win,” said Williams, who will face Anastasija Sevastova for the first time for a place in the final after the 19th seeded Latvian knocked out defending champion Sloane Stephens, the World No.3.

The departures of Stephens and Pliskova left 14th-seeded Madison Keys and Williams - seeded 17th despite her world 26 ranking - as the highest seeds remaining in the women's draw.

Keys faced Spain's Carla Suarez Navarro for a semifinal berth on Wednesday, with the winner to face either Japan's Naomi Osaka or Lesia Tsurenko of Ukraine.

Pliskova, who seized the world number one ranking herself briefly last year, said that even though Williams is still rebuilding her world ranking, she's playing more like her old number one self than a number 17.

“She's playing with the same power. She can still serve well,” Pliskova said. “I don't think there's any change with her game. She's just going for her shots.”

That's good news for the 36-year-old Williams as she vies for a title that would see her break out of a tie with Chris Evert for most US Open victories and equal Australian Margaret Court's all-time record of 24 major titles.

While she says she doesn't feel pressure, she admits that she savors every opportunity more now.

“I don't have 10 more years, at least I don't think so - I said that 10 years ago.

“I don't think I have another 10 years of having opportunities to be able to play and win championships. Every match really means a lot to me.”