Andy must be beyond tired. But the no1 goal may be driving him - he knows it won't come without super-human effort so maybe he is thinking that he must try for any catch up ground he can gain
He also believes in taking care of his body, so that might just take priority here, particularly with the USO and DC coming up. By the same token if he can keep himself fit and injury-free then I'd say he's got more of a chance of achieving #1 next year. Djoko on the other hand has hammered his to achieve his ambition and more, so could now perhaps be something of a spent force, unless he stages one of his remarkable recoveries very soon.