I think Nishikori has a good chance against Cilic. He runs down a lot of the balls and is a good returner.
The way Nole is playing, should be an easy run to the finals.
Hopefully Del Potro and Nadal run each other around the court in the heat/humidity of New York.
Nadal also has to play Thiem who is looking better and better with each passing tourney. A guy who will probably win quite a few slams in his career once Djokovic, Fed, Murray and Nadal retire.
So, Djokovic has a chance to win his 3rd US Open title and head to AO with a lot of motivation/confidence because now Nole, Fed and Emerson sit at 6 titles a piece at AO.
Winning the next two slams would put him ahead of Sampras and IMO you have the 3 GOATS in Rafa, Nole, and Fed at the top and it will be VERY hard to ever overtake any of those 3 guys.