Williams earned her 17th major title at the U.S. Open this month. Graf, who won 22 Grand Slam singles titles, believes Williams will surpass leader Margaret Court at 24.
"She's got a lot of tennis left in her,'' Graf said. "I can easily see her pass all of our records. I don't see the competition catching up to her.''
These days, the 44-year old Graf is busy raising 11-year-old Jaden and 9-year old Jaz, who enjoy baseball and dance.
Graf attended an event in New York and promoted her foundation "Children for Tomorrow,'' which works with youth traumatized by war.