The 40-year old Williams, who is more than two decades older than her 19-year-old opponent, was the top-ranked player in the world when Raducanu was born in November of 2002.
If the Spaniard wins the ATP Masters 1000 title and current World No. 1 Daniil Medvedev fails to reach the quarterfinals, Nadal would rise to the top of the ATP Rankings.
Djokovic posted a note to his fans on social media after the announcement
Elsewhere, Karolina Pliskova defeated Denmark's fifth-ranked Caroline Wozniacki 6-2, 6-4.
Next for Nadal is a third-round matchup with 24th-ranked countryman Albert Ramos-Vinolas.
The 31-year-old Berdych, the World No.15, fell apart in the third set, failing to hold serve.
Meanwhile, Rohan Bopanna and Ivan Dodig of Croatia have got a first round bye.
