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

The red carpet rolled out at Arthur Ashe Stadium. Smoke blew from the cannons. Then Maria Sharapova emerged in a mid-length black dress, its collar reflecting light back into the tennis stratosphere,

When Sharapova was inducted into the Tennis Hall of Fame on Saturday night, her former on-court antagonist provided the introduction. For many tennis watchers, Williams’s top-secret cameo was shocking but the moment capped a 180-degree turn in their once pointy rivalry.