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.

Hall of Famers Martina Navratilova, Jim Courier, Stan Smith and Andy Roddick were among those in the crowd, wearing their blue Hall of Fame blazers. Sharapova and the Bryan brothers also received a cast tennis racket that is the hall’s newest offering to inductees.

Williams and Sharapova were not always on great terms, each admitted in their speeches, but came to share a mutual respect and a growing friendship since retiring.