Elena Rybakina reached two milestones on Wednesday, September 9: her first US Open semifinal and a guaranteed debut at world No. 1. The second seed defeated qualifier Zheng Qinwen 3-6, 6-1, 6-4 in two hours and 14 minutes on Arthur Ashe Stadium.
The ranking change takes effect on Monday, September 14, after the tournament. In its official announcement, the WTA confirmed that Rybakina will replace Aryna Sabalenka, becoming the 30th woman to lead the singles rankings and the first player representing Kazakhstan to achieve the distinction.
The victory required two recoveries. Zheng took the opening set after saving five break points in the final game, eventually converting her fourth set point. Rybakina answered with a commanding second set to send the match into a decider.
The critical moment came with Zheng leading 4-3 in the third: the Chinese player held a break point for a 5-3 advantage. Rybakina moved forward, and Zheng's attempted backhand pass went long. From there, Rybakina won the final three games to complete the turnaround.
It was the third time in three meetings this season that Rybakina had beaten Zheng after dropping the first set. The previous comebacks came in Doha and Madrid. Her New York victory extended her lead in their head-to-head to 5-1.
Her ascent also rests on earlier results: titles in Ningbo and at the WTA Finals late in 2025, followed by the Australian Open and Stuttgart in 2026. Before this US Open, she still had to test an injured left ankle. She reached the quarterfinals without losing a set, including a fourth-round victory over Naomi Osaka.
The ranking is secured, while the title remains in play. The embedded video shows the quarterfinal highlights from the official US Open channel.
Sources: the US Open match report; the WTA's match coverage, No. 1 announcement and feature on Rybakina's path to the top, published on September 9, 2026.