Most of the success for Crabtree was against Humphrey. Kid still has some developing to do which isn't surprising. He underestimated how physical Crabtree would be in fighting for a first down when he caught it short of the sticks; a good/less casual tackle there would have prevented the TD drive. Jimmy came back in after a couple drives off and things looked a lot better. Carr got burned when Manuel escaped the pass rush, but that's kind of like a broken play. I think it was a strong defensive performance overall.
I don't think the game briefly being a one score contest for a 5 minute stretch in the second half means that it was closer than the score indicates. It's rare that a game has 0 drama, and it's not like they ever tied or led outside the very early portions of the game. It was a pretty smooth win; which is what we should hope for against a backup QB.