Ashleigh Barty moved to within two matches of becoming world number one after beating Venus Williams 6-4 6-3 to reach the semi-finals of the Nature Valley Classic in Birmingham.
The French Open champion will overtake Naomi Osaka at the top of the rankings if she wins the title on Sunday.
Barty, 23, won five games in a row to take the first set and then broke Williams' serve twice in the second.
The Australian will face Barbora Strycova in the semi-finals.