Williams, 39, is chasing the record for 24 Grand Slam titles next week.
She does so after returning from the injury she has had in her heel since the US Open in September.
In a pre-tournament before the Australian Open, she was back and defeated 452-ranked Daria Gavrilova in two straight sets, 6-1.6-4.
At first she did not think that it had taken so long for Williams to recover.
- Heels are honestly the worst. Oh my God, I did not think it would take this long. I pushed myself to the limit, but now I'm here, she says.