I find it interesting that you say that because Dann Quinn, the guy whose team is about to head to the NFC Championship game with a rookie QB, is also the HC that blew a 28-3 lead in the Super Bowl. That "ain't one game" and yet it was one game and he's clearly still a very good head coach despite having a horrible game on the biggest stage and in the biggest game of his career.
Is blowing a 28-3 lead in the Super Bowl a red flag?