The offense handed the outcome of the game over to the defense with the lead. No matter how they obtained that lead, it still was the lead. The defense does their job upon their last time on the field, the Saints win.
Yeah.... never mind what happened the other 56 minutes of game time.
Of course, the only reason why the offense "handed a lead" to the defense was because the defense held the Eagles scoreless for 3+ quarters, and kept giving the ball back to the offense. You don't win many games scoring 12 points only. That the offense "handed a lead" to the defense when they scored 12 points should tell you how good the defense played.
Never mind the missed extra point and the dumb decision not to kick a field goal and get stuffed on 4th down.
The defense kept on making up for the offense's ineptitude the entire game.
The game ended by the offense throwing an interception, BTW.