Through seven games, the New England Patriots remain undefeated — and they appear unstoppable. No longer a team defined by the play of quarterback Tom Brady, New England is fielding one of the most dominant defenses in NFL history. The 48 total points allowed by New England heading into Week 8 are the lowest since the AFL-NFL merger and the second-lowest on record, trailing only the Otto Graham-led 1946 Cleveland Browns. The Patriots’ score differential of 175 points is the best all time through seven games, and perhaps because of that, our Elo forecasts have New England as a virtual lock to make the playoffs. History agrees: No team since the 1948 San Francisco 49ers has started a season 7-0 and missed the playoffs.

The defensive dominance starts up front in New England. The Patriots have been aggressive rushing the passer, ranking seventh in the league in blitzes (82) and first in defensive EPA on those plays (30.2). The high EPA total is due in large part to the Patriots’ league-leading five interceptions off the blitz — but it’s not just a few lucky interceptions boosting their numbers. New England has been consistently good when blitzing, gaining positive EPA on 70.7 percent of their blitzes, 17 percentage points over the league average. Overall, New England is second in the league in sacks (26) this season.

Perhaps the Patriots’ Achilles’ heel on defense is that — despite their gaudy sack totals — they’re actually below average at pressuring the opposing quarterback. According to ESPN Analytics’ Pass Rush Win Rate metric, the Patriots are in the bottom third of the league (24th) in generating pressure. And despite their early-season dominance, this could end up being a problem for the Pats as their schedule gets harder in the second half of the season. While hand-wringing about seemingly small defensive flaws in the face of New England’s historic performance might seem misplaced — no dip in performance will likely be large enough to keep them out of the postseason — the lack of pressure is still notable.

Pressuring the quarterback and effective pass coverage are interconnected. It’s probably unsurprising that when quarterbacks aren’t pressured, their passes are worth significantly more than the throws they attempt when under pressure. What’s more interesting is why those unpressured passes are more valuable.

It turns out that the pass attempts that really end up hurting a defense are the deep shots taken by an offense when its quarterback has time in the pocket. Throws with target depths of 20 air yards or more are significantly more valuable than those thrown short (from 1-to-10 yards), and unpressured quarterbacks with time in the pocket tend to attempt more of them. The Patriots have a low Pass Rush Win Rate, so we might expect them to have seen quite a few deep passes attempted against them this year — and that’s just what we find. No other team has had more passes of 20-plus yards thrown against them this season.

Offenses like to attack New England deep Number of deep passes attempted against teams and their defensive outcomes in the 2019 regular season through Week 7 Deep passes attempted against Defense Record Total avg. Yards per attempt Defensive EPA defensive Success rate New England 7-0-0 42 4.3 +29.6 88.1% Detroit 2-3-1 39 10.9 -12.9 69.2 Kansas City 5-2-0 38 10.7 -17.6 68.4 Houston 4-3-0 35 9.2 -6.8 68.6 Baltimore 5-2-0 34 16.3 -23.4 61.8 Jacksonville 3-4-0 33 13.7 -15.5 63.6 Oakland 3-3-0 33 20.7 -57.6 42.4 Minnesota 5-2-0 33 10.2 -8.3 69.7 Green Bay 6-1-0 32 19.6 -33.3 50.0 N.Y. Giants 2-5-0 30 16.2 -21.4 50.0 New Orleans 6-1-0 30 17.7 -22.5 53.3 Philadelphia 3-4-0 30 15.2 -16.5 63.3 Carolina 4-2-0 29 7.0 +1.7 69.0 Cincinnati 0-7-0 29 14.8 -22.3 55.2 Dallas 4-3-0 28 11.8 -13.3 67.9 Tampa Bay 2-4-0 28 13.9 -17.3 60.7 Miami 0-6-0 27 16.2 -25.1 51.9 Tennessee 3-4-0 27 12.0 -5.5 59.3 Arizona 3-3-1 26 14.5 -25.9 46.2 Atlanta 1-6-0 24 19.5 -29.4 45.8 Denver 2-5-0 24 11.8 -9.4 62.5 N.Y. Jets 1-5-0 24 13.3 -19.4 50.0 Buffalo 5-1-0 23 8.8 +1.3 73.9 Indianapolis 4-2-0 20 14.4 -12.2 55.0 Seattle 5-2-0 20 16.8 -22.4 55.0 San Francisco 6-0-0 19 4.5 +12.4 89.5 Washington 1-6-0 19 15.6 -18.7 57.9 Pittsburgh 2-4-0 18 13.3 -10.1 61.1 L.A. Chargers 2-5-0 18 19.0 -13.1 44.4 Chicago 3-3-0 16 12.1 -2.0 68.8 L.A. Rams 4-3-0 15 15.9 -4.8 60.0 Cleveland Browns 2-4-0 13 9.6 -1.4 69.2 Deep passes are pass attempts that travel 20 yards in the air. Source: ESPN Stats & Information Group

Attempted passes aren’t completed passes, of course, and the Patriots have been incredible at defending the deep ball all year long. Of the 12 defenses that have seen 30 or more deep pass attempts against them, the Patriots’ secondary is the one defensive unit with a positive EPA. Not only is New England allowing just 4.3 yards per play on passes of 20 yards or more, 37 of the 42 deep passes attempted against the Patriots’ secondary ended up as negative EPA plays for the opposing offense. As a percentage of those plays, only the San Francisco 49ers have performed better against the deep ball through Week 7. And according to the NFL’s Next Gen Stats, teams are completing passes 24 percentage points below what we’d expect against the Patriots on deep passes.

Can New England keep up this blistering pace? We know that defensive performance is unpredictable, and that fortunes can change quickly in the NFL. The Pats will go from facing Ryan Fitzpatrick/Josh Rosen, Luke Falk, Josh Allen/Matt Barkley, Colt McCoy, Daniel Jones and Sam Darnold over the past six weeks to Baker Mayfield, Lamar Jackson, Carson Wentz, Dak Prescott, Deshaun Watson and perhaps Patrick Mahomes in the next six games. Given their upcoming opponents, it’s probably inevitable that New England’s current defensive performance will come back down to earth. But if the Patriots can improve their pressure on the quarterback, denying some of the league’s best signal-callers a clean pocket from which to attack them deep, their chances of continuing to defy gravity might improve substantially.

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