I would say that his passer rating which in terms of his career is in the Top-5 and that is against all opponents placed in front of him. Narrowing down to just comebacks doesn't really tell the whole story. But that said this is the NFL. 4th quarter comebacks are difficult no matter who you are playing. Especially when doing it with a weak supporting cast. Last year he made a 4th Qtr. comeback against the NFC Champion 49ers on the road and he did it with a punctured lung.