PARIS — Serena Williams knew, of course, that 11 years had passed since her only French Open championship. She also knew, of course, what happened a year ago in Paris: the only first-round Grand Slam loss of her career, to a woman ranked outside the top 100, no less. Eager to repeat the elation of 2002, and motivated by the disappointment of 2012, Williams used terrific defense and her usual powerful hitting in Saturday's final, closing with a crescendo of aces — three in the last game — for a 6-4, 6-4 victory over defending champion Maria Sharapova to collect a second Roland Garros title and 16th major trophy overall.