At the halfway mark, Patriots are:
5th in Points Allowed (17.9 PPG, just 0.5 PPG more than the #1 Broncos)
8th in Yards/G allowed
7th in Yards/Play
3rd in Rushing Yards allowed
10th in Passing Yards allowed
8th in Passer Rating allowed
2nd in Sacks
7th in INT
10th in Passes Defended
14th in Forced Fumbles
Top ten across the board, which is especially impressive for passing stats considering the garbage time. Patriots point differential: 133, ~16.6 PPG
Top 4 defenses (PPG): ~ 6.1 PPG diff
Looking at yardage stats:
Top 7 defenses (total yards): ~ 4.2 PPG diff
So the Patriots are winning by an average of 10.5 - 12.4 MORE points per game than the defenses statistically better. We've seen this team let up once the game is out of reach (today a prime example), and it happens WAY more often than any other team, let alone the defenses 'better' than the Patriots.
It's a top 10 defense. Case closed.