OK, I already walked you through how the defense held up after the strategy shift, and how they executed that new plan perfectly. I could also have talked about how, before the strategy shifted at 21-6, the Patriots D had forced 2 punts, 2 FGs and a fumble in 5 defensive drives, clearly an excellent performance. But now the goalposts have moved: success rate on third down! Alex Smith rushing! QB pressures! Let's look at each of these in order.
Third Down success rate. Let's start with FO's Drive Success Rate to give us some general stats for context. Drive Success Rate is the % of down-series (i.e., new first downs) which result in a first down or a touchdown (i.e., the drive continues or finishes successfully). ARI had the #1 offensive DSR with .751, and the NYJ the best defensive DSR with .632.
NE: Offensive DSR .724 (#7), Defensive DSR .666 (#8), Net DSR +.058 (#4).
KC: Offensive DSR .687 (#18), Defensive DSR .680 (#11), Net DSR +.007 (#13)
How'd they do Saturday? I'm adding this up by hand from the PFR play-by-play, but by my numbers:
NE offense: 27 series starts, 21 successes = .777 DSR
KC offense: 35 series starts, 27 successes = .771 DSR
OK, but how about 3rd downs? Excluding kneel-downs, I've got NE converting 6 of 8 third downs in the first half (the last of which was the 1-yd Brady dive for a TD), but 0 for the 3 in the second half, all of which were passes in the 4th quarter. That's 6/11 = 55% total. However, on 1st and 2nd down, they picked up a new set of downs (or a TD) on 15 of 43 snaps = 35%.
KC, meanwhile was in far more desperate straits, lining up for 21 third downs and converting 13 (62%), and of the 8 failures, they went for it 3 times and succeeded on 2 (they also punted 3 times and kicked 2 FGs). But out of 64 snaps on 1st and 2nd down, they converted on only 12 of them (19%).
So I'd say that, yes, KC was able to convert 3rd downs more often than you'd like (NFL average this year was 39%), but so did the Patriots. And KC's third down count was very high, mostly because the defense was playing so well on 1st and 2nd down - and forced a fumble, as well as the 4th-quarter turnover on downs. I'm not seeing this as a big knock on the Pats D, more the result of a tactical decision.
Alex Smith Rushing. For the season, Smith rushed 84 times (5.3/game) for 498 yards (31.1/game), good for a 5.9 Y/A. Saturday, he tried to run (or, well, failed to pass) on 10 occasions. One of those, at the start of the 4th, he got sacked by Chandler Jones for -3. The other 9 were:
2nd and 10, NE 44: right end for -3 yards (was this really a sack? Q1, 5:26 remaining)
3rd and 13, NE 47: left tackle for 15 yards (this one was the big, frustrating one on the day)
3rd and 1, NE 11: right guard for 2 yards
1st and 10, KC 25: left tackle for no gain (was this really a sack? 1st play of 3rd Q)
3rd and 3, NE 29: scramble for 7 yards
1st and 10, KC 20: scramble for 2 yards
1st and 10, NE 47: left end for 9 yards
1st and 10, NE 32: scramble for 6 yards
2nd and 4, NE 26: up the middle for 6 yards
Total: 41 yards rushing, 4.6 Y/A.
Those last 4 on that list were all on KC's final drive, so it was clearly Alex Smith getting desperate (and/or NE's pass defense giving him no downfield options). Most of the others were tiny gainers, or losses, where we clearly didn't lose contain. Only his 2nd rush was a very concerning play - and that was mid-1st quarter and they basically tightened up on him after that. He ended well below his season Y/A, and not much above his season total in yards. This was not a
Tebow-in-2011 type performance (or, worse a
Carolina-in-2013 one) where the Patriots D was unable to stop a mobile QB.
QB Pressures. So first off, obviously, the Patriots' OL had an incredible game, with Brady getting his jersey dirty only twice, one of which was a late hit that got KC a 15-yard PF. On the other side of the ball, you had all of the Smith rushes above, most of which weren't designed rushes and were scrambles indicative of QB pressure. You've got the 1 sack and two quasi-sacks, plus a fourth short gainer on 1st-and-10. I can't find a good source on how many QB hits we got on Saturday, but for the season, KC gave up very few (4.9/g, 24th in the NFL), and had 9 in their 2 postseason games. Then there's the whole NY/A stat: 7.2 NY/A for Brady, 4.8 for Smith. My eyes told me we were keeping him contained, pressured, and usually without good pass targets on the day, and the stats certainly don't say otherwise.
So overall, I'll continue to disagree that the D had a bad day.