It looked like the heat was getting to him. A bit sluggish to me. Wish he would get a better return of serve- he would be so much harder to beat that way.
Yeah, the heat always does seem to bother Isner more than his opponents. You would think he would be more used to it since he trains in Florida. His return has improved some over the years, but it does have a long way to go. I think he needs to improve his return, backhand, and volleys if he wants to consistently beat top players.