Bill Clinton comes to the defense of Serena Williams in the new documentary "Venus and Serena." The former president, calling himself a "sports fan," reminisces on camera about first seeing the tennis star play at 17, when he said she exuded an "aura" that convinced him "once she mastered her power nobody would be able to beat her."

Clinton pops up again later in the documentary -- following Chris Rock, another Serena defender -- to downplay the controversy over Williams's well-publicized 2009 penalty for unsportsmanlike conduct.

"When I see a great athlete do something that seems self-destructive, I always think: 'We should cut them a little slack,' " Clinton says in the film, available on iTunes now and in theaters May 10. "I didn't pay much attention to it. I still like her."