The winners could face 24-time grand slam champion Novak Djokovic and his partner Olga Danilovic if the Serbian pair overcome Mirra Andreeva and Daniil Medvedev.
Venus Williams, at the age of 45, faces Karolina Muchova and Andrey Rublev alongside compatriot Reilly Opelka.
The competition features a 16-pair event, with new rules for the tournament that include sets won by four games (excluding the final), no-advantage scoring, and a 10-point match tie-break in place of a third set.