The grimaces on the face of Rafael Nadal were the first indication that something was wrong. Then he asked for the trainer to tape his right knee. Then, in the biggest sign of all, he allowed a ball to whiz past him without even a chase.
Then, in a moment of pique with the chair umpire in the second set, Nadal told him that he was going to retire.
A few games later, Nadal did. After spending more than 17 grueling hours on court during the United States Open, his 32-year-old body gave way.
