There are defeats that arrive quietly and those that announce themselves with something closer to collapse, and Novak Djokovic's exit from Roland Garros on Sunday belonged unmistakably to the latter category. The 24-time grand slam champion, whose capacity to survive the unsurvivable has long been regarded as one of sport's most dependable certainties, was beaten 4-6, 4-6, 6-3, 7-5, 7-5 across four hours and fifty-three minutes by João Fonseca, a nineteen-year-old Brazilian whose composure under pressure is considered extraordinary even by those who have followed his rapid ascent closely. What made the defeat particularly striking was the position from which Djokovic appeared to be winning. A two-set lead had been established against an opponent two decades his junior, and yet the match's momentum shifted irrevocably in ways that even Djokovic himself seemed unable to arrest. At one point, having returned to his chair in visible distress, the thirty-nine-year-old was seen vomiting onto the clay, a moment that appeared to encapsulate the physical toll that a three-month injury absence had quietly imposed upon his preparations for the tournament. Fonseca, for his part, is said to have approached the occasion with a disarming simplicity. When asked on court about the self-belief that had carried him through, he offered little in the way of elaborate analysis. "I just played," he said. "I just enjoyed being on court." It was a remark that, while modest in tone, might reasonably be understood to reflect a mental maturity that belies his age. Djokovic, to his considerable credit, was generous in defeat.…