Personally, I don't feel as though you should discredit the Colts offense as much as you should credit the Patriots defence. Remember, coming in, almost every "analyst" said that the Patriots secondary would not be able to keep up. Due to injuries (Law, Poole, Seymour, etc) the Pat's defense was as vulnerable as it's ever been.
Well, it shows how much they know.
Besides, you can't knock Peyton for one underpar game when he'd destoryed every team during the regular season. Sure, maybe he hasn't got that "big game" under his belt yet, but he sure is dangerous out there at any time.