WHEN SHE ARRIVED IN PARIS this week as the defending champion at the French Open, Maria Sharapova was fresh off her win at the Italian Open in Rome and had a shiny new trophy and a bag full of cash to show for it. Both tournaments are played on red clay, which she has said made her feel like “a cow on ice.” But she’s hardly bovine. A lean 6-foot-2, with an imperial persona on the court and a sunny California élan off it, Ms. Sharapova, 28, is currently No. 2 in the world, a ranking she earned in part with her powerful two-handed backhand accompanied by a shriek that gives voice to her competitiveness. Other Sharapova...