Garbine Muguruza, the 2016 women’s champion, is already on court, playing French wild-card entry Fiona Ferro for a spot in the third round.
Nadal, chasing a record-extending 11th men’s title, will play Guido Pella in the second round.
After a straight-set win in her first Grand Slam match following maternity leave, Williams will face a tougher test against 17th-seeded Ash Barty.
Two-time champion Maria Sharapova is also in action later against Donna Vekic.
The skies are sunny, with no sign of possible storms forecast for the afternoon.
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