Isner has regressed to how he played in 2007 when he first burst onto the scene. Terrible approach shots/volleys, inconsistent forehand, thrown away games, awful returns, etc. Great serve is about it, and even that wasn't too hot today.
Maybe the injury he got last year which hurt him at the USO has caused a mental block, maybe Querrey brought him down to his level, who knows. Isner has already lost a bunch of points this year and he's in danger of losing his seeding. Whatever's going on, get it together John