Watching the highlights one can easily remark that he hits pretty often only 1m beyond service square, which is way too short especially on clay where his spin isn't annoying for most opponents. Delbo played a really solid match there, with a bit of luck at the net when he needed it.
Another area where Fed was disappointing is the serve return, mostly casual and not trying to block it efficiently as he used to do it so often back in RG 2009 for example.
Basically once he played deeper shots and more risky returns, he controlled most rallies, but it seems he only relied on his talent, which isn't a good sign for the upcoming tournies.