Rafael Nadal plays favorite as he pursues his 16th Grand Slam title at the U.S. Open

The door was opened for surprises in the U.S. Open men’s field when injuries took out Novak Djokovic and Stan Wawrinka before the tournament began, and it opened wider when the late withdrawal of No. 2 seed Andy Murray shook up the bottom of the draw. The struggles of a subpar Roger Federer — who...