Simona Halep has become world number one for the first time by beating Jelena Ostapenko to reach the final of the China Open.
Romanian Halep won 6-2 6-4 in Beijing and will replace Spain's Garbine Muguruza at the top of the rankings.
She will face France's Caroline Garcia, who beat Petra Kvitova of the Czech Republic 6-3 7-5, in Sunday's final.
Garcia also maintained her hopes of denying Britain's Johanna Konta a place at the WTA Finals.
If the Frenchwoman wins the China Open, Konta must reach the final of the Kremlin Cup, which starts on 16 October, to claim the eighth and final place at the season finale in Singapore.