Didn't Dent take out Hewitt earlier this year in a tournament? Maybe I'm wrong (not being sarcastic, I really can't remember). Also consider that Hewitt isn't playing his best after coming back from injury; Dent's playing decently.
On an extremely good day, he could get past Hewitt, but I don't see him beating Ancic; not on grass. I'd be thoroughly shocked if Dent made it to the semis, where he'd be sorry for making it that far to play Fed.