i dont think i've ever seen him play this poorly before
i wonder if the thought of playing one of the big 3 gets to him? in all his losses i think his worst matches have always been a round before he rean into one of them
I agree that he was playing quite badly. 54% 1st serve and a ton of really wild Backhand errors. He also never changed his approach on the return, I think he could have tried moving up and attacking the net more.
On the positive side, he did very good not losing his shit at the umpire in the 3rd set when he just gave Monaco a set point, and he did a good job winning points on second serve.