Novak Djokovic's disappointing post-U.S. Open swing turned even worse after a straight-sets thumping to David Ferrer at the World Tour Finals.
Andy Murray reverted to the petulant lad he can be when things go awry. And things were going awry at the World Tour Finals.
Eight players, two groups and, ultimately, one winner. Andy Murray's pool is going to be tough. Question is: Will he swim or sink?