Garbine Muguruza retired through illness from her China Open first-round match against Barbora Strycova on Monday.
The world number one was evidently not at full tilt in Beijing and she was broken in the first game en route to losing the opening set 6-1.
Strycova was a break up in the second set when her opponent called it quits, meaning the Czech will face Julia Goerges in the second round.
The withdrawal of the top seed opens up the draw to a number of hopefuls, with the likes of Simona Halep, Elina Svitolina and Caroline Wozniacki in action at the WTA Premier event.