PARIS — In his mind, as Roger Federer imagined over the years and the frustration what it would be like to finally win the French Open, it was probably not quite like this. How could Federer have imagined that the obstacle across the net in one of the most important matches of his life would be Robin Soderling, a relatively anonymous Swede, instead of Rafael Nadal, his left-handed Spanish nemesis? How could Federer have imagined that with him cruising comfortably early in the second set Sunday, an intruder would jump out of the stands and onto the clay, run toward...