In the long arc of tennis greatness, Thursday's US Open semifinals offered a study in momentum and mastery. Elena Rybakina dismantled Coco Gauff's 11-match winning streak in three hard-fought sets, while Aryna Sabalenka moved with quiet inevitability past Jessica Pegula, placing herself one victory away from joining a very short list of women who have claimed three consecutive US Open titles. What remains is a final between two players who represent different kinds of excellence — one ascending on the strength of a remarkable season, the other pressing toward history that has not been made in