French Open champion Ashleigh Barty can become world number one for the first time after rival Naomi Osaka suffered an early setback on grass.

The likelihood of Australian Barty jumping to the top spot grew on Thursday when WTA rankings leader Osaka was beaten in the last 16 of the Birmingham Classic.

Osaka slipped to a 6-2 6-3 defeat against Kazakhstan's world number 43 Yulia Putintseva, dealing a blow to her preparations for Wimbledon.

Second seed Barty went safely through to the quarter-finals as a 6-3 6-1 winner against American Jennifer Brady but must capture the title on Sunday to depose Osaka.