Simona Halep will take over the top ranking after reaching the China Open final on Saturday, and Rafael Nadal will play Nick Kyrgios for the men's title.
Halep beat French Open champion Jelena Ostapenko 6-2, 6-4, ensuring that when the WTA rankings are updated on Monday she will be the first women's No. 1 from Romania.
Halep could have reached No. 1 earlier but was upset in the French Open final by Ostapenko in their first career meeting.