Well, if Bill was smart he watched our game and learned from it. He is smart, so that happened.
Rams switched up some tendencies for our game, when the later half of the season they had some trouble against things we did, they planned for us approaching it the same way. They went into the game showing classic cover 3, single high, and man beating personnel groups. And from the get go, the entire plan was to beat up on our DT's and take advantage of DE's in our nickel packages when they figured out we were probably going to do what had been decently successful against them previously.
The book on Goff was he was bad under pressure, and beating the Rams OL straight up would be tough sledding (especially after the effort vs the Colts). The Rams OTs had a great year, and their interior OL was still good, but the C was the weakest link 2nd half of the season, and I guess we thought we had better odds of creating pressure against the interior guys C/RG/LG if we used some of the speed and length we had at DE to stunt/twist and create favorable matchups or even catch them off balance a few times. We'd been pretty good vs the run all year so I guess we thought we'd be okay there while still creating some pressure.
And we got killed. They knew the tendencies of the twists/stunts and were planning on disguising runs anyway, so they prepared for it. I'm not exactly sure how long we stuck with it, but it looks like we were smoked pretty early.
The Patriots played them more straight up while shooting upfield. Very gap disciplined. Give their secondary and Belichek credit because they absolutely smothered their routes/tendencies in the pass game. They continuously got pressure by sending pressure up the A and B gaps, leaving DEs to occupy the OTs and DTs to try and get upfield/draw double teams. I was continuously surprised by the punches that troubled Havenstein pretty frequently. It looks like the plan there was to punch and drive Havenstein consistently, while playing the cutback in the run game but often bringing a 5th guy up the A/B gap. They worked to create space in these gaps.
Belichek is also a defensive mastermind, so there's that. Arguably the best NFL mind of all time. That helps.