Venus Williams beat Kournikova 6-3, 6-2 in a singles match during the exhibition, which raised money for several charities.
Kournikova dropped four straight games to lose the first set before taking a brief lead in the second.
In the second set, Kournikova handed over her racket to a fan, giving him a chance to return Williams' powerful serve. The fan swung and missed. Venus Williams' serve has topped 127 mph.
Kournikova has not played competitive tennis in 18 months because of injuries.
The players appreciated the casual pace of the exhibition.
``You play looser,'' Venus Williams said. ``All of your shots go in.''
The event benefited several charities, including the Tubby Smith Foundation, the Jamal Mashburn Excel Scholarship Fund and The Owl Foundation, a charity founded by Williams' mother, Oracene Price.