By far, defeating the Saints is their most impressive win.
Firstly, the game plan had to be an excellent one in order to defeat Drew Brees and the talented Saints' Offense.
This was not a game that could be won by better talent, because the Patriots did not have better talent available at this particular time. The Pats have too many weapons missing from their offense, and injuries are taking their tole on the Defense as well.
Nor could they rely on Brady's experience and savvy to lead them past the Defense, this was not the Falcons' Defense which was fielding two rookie CBs and is led by a sub-par DC. These Saints were led by Rob Ryan, and had a Secondary made up of capable, if not star worthy, players.
The Defense took away Jimmy Graham, who was the leading receiver in the NFL coming into the game. The Defense limited the damage done by the dynamic Sproles as well. And despite the Patriots' offense looking less than stellar for almost the entire 2nd half, the D kept them in the game.
This honestly was a game the Pats should not have won, not with the offense spending most of the second half sputtering and bumbling away every opportunity given them. Brady's game winning drive is all that keeps that from being one of the most pathetic halves of football the offense has produced to date this season.
The Patriots found a way to win against one of the best coached and best playing teams in the NFL, despite some of their best players not being out on the field when they did so.
That is quite an accomplishment. And speaks a lot about the toughness of this year's team.