LOOK BACK: Serena vs. Sharapova, an enduring rivalry

PARIS (AP) — Through 14 years and 21 matches, Serena Williams vs. Maria Sharapova has evolved into one of the most enduring and multi-faceted, if also lopsided, rivalries in women's sport.

The next episode comes Monday, in their fourth-round match at the French Open.

They speak with respect for each other's tennis and achievements. They are among the highest-paid women athletes in history, having banked more than $100 million in prize money between them. They both had tough childhoods. And with their intense, almost primeval competitive drive, they have blazed trails in women's tennis and forced the next generation of players to up their game.