Elena Rybakina is the new world number one after coming from behind to beat Zheng Qinwen and reach the US Open semi-final for the first time.

Qualifier Zheng enjoyed a formidable run to the last eight, but she could not hold off Rybakina's fightback, with the Kazakh recording a 3-6 6-1 6-4 victory in two hours and 14 minutes.

Having blown away Iga Swiatek last time out, Zheng came out strong in the first set, though the pair were evenly matched through the first six games.

Zheng won the final three games, but had to fight to get over the line, finally converting her fourth set point after fending off five break points for Rybakina.

The number two seed immediately shook off that disappointment, dropping just one game in the second set as she forced a decider.

Zheng stayed strong on serve to take a 4-3 lead in the third set, only to fail to convert a break point that would have left her serving for the match.

And it was the motivation Rybakina needed as she ultimately won the final three games in a row to surge over the finish line and make it through to the last four, where she will face Mirra Andreeva or Coco Gauff.

Introducing your NEW WTA No.1 Presented by PIF, Elena Rybakina! @PIF_en | #PIFWTARankings pic.twitter.com/aaX304amoe

— wta (@WTA) September 9, 2026

Rybakina reaches new heights

Aryna Sabalenka has been the world number one for the last 99 weeks, but she falls just short of a century despite still having the chance to claim a three-peat at Flushing Meadows.

Rybakina has kept plugging away at the gap, though, and overcame an injury doubt ahead of the US Open to ensure she would have the chance to catch the Belarusian.

"It's just a number right now," Rybakina said. "Of course, I'm in the semis, so my goal is to win the tournaments which I play. 

"I go just match at a time. It's an amazing achievement, but you know how quick everything can change in tennis, ranking-wise, during the match. I just need to focus on my game, try to recover and enjoy [the semi-final]."

Since 1975, Rybakina (27 years, 89 days) is the second-oldest player to first obtain the world number one ranking, after Angelique Kerber (28y 238d).

She is also one of the three players representing an Asian country to reach the semi-finals of both the Australian Open and US Open in the Open Era, along with Li Na and Naomi Osaka.

It is the third time in as many meetings this year that Rybakina has defeated Zheng from a set down, and it means that only fellow semi-finalist Jessica Pegula (50-12) has won more tour-level matches in 2026 (47-13).