Maria Sharapova, a three-time Grand Slam singles winner, has made a career of thriving in the big moments. Mental toughness has been her calling card. We take you now to the fourth game of Monday's fourth-round match with No. 1 seed Caroline Wozniacki. The willowy Russian was serving to level the match that had yet to find a rhythm, and she had a game point on her racket. And then, incredibly: Double fault. Double fault. Double fault.