Champions don't take the field for their final and most important drive of the season with 88 yards behind them and not even be competitive while watching the other team walk right down the field at will.
Well, the 2007 Giants - the World Champion Giants - did just that, essentially. Leading 10-7, the Giants gave the ball back to the Patriots, who then proceeded to march 80 yards in 12 plays to score with just over 2 1/2 minutes left on the clock. The only 3rd down on the play was the TD to Moss.
So, faced with the prospect of holding a lead or letting the other team march down for the likely win, the fabled 2007 Giants defense saw the Patriots just cut them to pieces play after play to take the go-ahead lead.
Of course, there was enough time on the clock for the Giants to have their own game-winning drive (aided by some miraculous stuff), but that's beside the point, which is that their championship defense, when faced with stopping NE and ending the game, absolutely, positively failed to do it and gave up the lead on their (NE's) last real drive of the game.
And that Giants' D did the same thing during the Pats' regular season game with them this year as well. They gave up 17 fourth-quarter points (and 20 points on four scores in NE's last 4 possessions), including the go-ahead TD (after NY was ahead 17-13) as they allowed the Patriots to drive 64 yards in 6 plays in just 1:27 to give NE what should have been the winning score.
Of course, in both these examples, the Giant offense bailed out the defense with a last-second drive of its own, but that doesn't change the fact that even their championship-caliber defense failed in both cases, and allowed NE, who was trailing, to drive down the field in the waning minutes of the 4th quarter to give the Pats the lead.
I haven't read the entire thread so maybe this point has already been covered. If so, forgive the repetition.