Williams' surprise appearance to induct Sharapova was "months in the making" and required the code name of another female icon.

Though Williams and Sharapova were rivals both on and off the court throughout their storied careers, they have unexpectedly emerged as friends since retiring. With their relationship now a friendship, Williams not only surprised Sharapova by attending her Hall of Fame induction, but gave a touching speech in her honor.

But the weekend stars shined a little brighter than expected when Serena Williams made a surprise appearance at the historic venue off Bellevue Avenue on Aug. 23. After years of battling each other on the court, Sharapova and Williams found the essence of one another.