The world number three suffered a leg injury as she slipped during her first-round match against Maria Joao Koehler earlier today.
She was able to continue and win the encounter 6-1 6-2, but the 23-year-old has revealed that the problem has caused her to suffer a lot of "pain".
"It's such a shock to me. I slipped and it felt like my whole body collapsed. I don't know what happened out there. I just tried to stay in the moment and give the best I could. It was definitely very emotional," she told BBC Sport.
"I was in such pain at the beginning, it wouldn't stop. I almost slipped one time before that. It shouldn't be like that on grass, we are not on clay anymore. I will do the best I can just to be ready for the next match and we will see what happens."
Should she overcome the problem, Azarenka will face Flavia Pennetta for a place in round three.