Victoria Azarenka is the only woman in history to defeat Serena Williams in four finals.

What's Vika's secret?

Watch: Serena Has Hilarious Chat With Kader Nouni

Belief and bravery on big points.

Asked to reflect on exactly how she beat the world No. 1 in the Indian Wells final, Azarenka initally deflected the question.

"I don't think you expect anybody to tell you right away, 'Hey, here is my game plan against the best player in the world,' " Azarenka told the media after her Miami Open third-round victory. "Since I won last time, let me give it out there so player can adjust."

The former No. 1 said you must bring your best to beat the 21-time Grand Slam champion.

"I don't think it's anything in particular," Azarenka said. "You have to expect to play your best tennis against player like Serena. You have to be brave to go for your shots. Mentally you got to believe."

"I think for me she's the greatest player of all-time. Whatever she plays, I think she's always going to look like a favorite," Azarenka said. "She's playing well. She didn't lose in first or second round. The finals are tough, but definitely going to be the biggest challenge."

Photo credit: BNP Paribas Open