I wish it were simply a strategy, or formula, but it was really just great pass defense. The 2009 Saints (#3) and 2010 Packers (#1) were among the league's best in defensive passer rating. Efficiency -- not yards -- is what wins games. In 2015, Dallas was #5 in the league in passing yards allowed, but 20th in DPR. If those rankings had been reversed, we'd have challenged for the division last year.
Defensive Passer Rating (Opposing QB's rating vs. Defense)
The first number includes all games in regular and postseason. The number in parentheses is postseason only.
SB winner's DPR
2010 Packers 67.3 (67.8)
2011 Giants 85.5 (83.1)
2012 Ravens 78.6 (72.4)
2013 Seahawks 65.1 (73.5)
2014 Patriots 82.3 (73.0)
2015 Broncos 76.2 (66.3)
AVG: 75.8
Playoff avg: 72.7
Cowboys' DPR
2010 92.8
2011 88.4
2012 94.7
2013 96.0
2014 90.4
2015 94.2
AVG: 92.8
Playoff avg: 104.8