The San Francisco 49ers' trip to face the Baltimore Ravens on Sunday marks the second consecutive week in which a top offense and top defense clash.
The Niners are coming off their most impressive performance all season, when they smothered Aaron Rodgers and Green Bay, but Sunday's challenge is an entirely different one.
Let's dive deep into the matchup, starting up front.
1. When the Ravens run
As much as Lamar Jackson has improved as a passer, the Ravens' offense always starts on the ground. The volume -- both in frequency and types of run schemes -- is vast, putting a lot on every defense's plate.
Only one team has held Baltimore to fewer than 5.1 yards per carry in a game: Pittsburgh at 3.5 in Week 5. The Steelers employed Bear fronts (covering both guards and the center) and even a rarely seen package with three D-linemen and five linebackers (and only three defensive backs).
The 49ers could mimic the Bear fronts and heavier personnel, but they'll do a few things differently. Coordinator Robert Saleh's D-line will likely feature Arik Armstead at left defensive end (instead of at tackle) and D.J. Jones -- a violent, sturdy run defender -- at nose tackle next to 3-technique DeForest Buckner. Along with right end Nick Bosa, that's a heavy front four.
Saleh could then opt for more speed at the second levels, playing nickel, dime or even dollar (seven DBs) packages, as the Chargers did in January's playoff win over the Ravens. Many teams match the Ravens' multi-TE sets with heavier personnel, but Mark Andrews is primarily a receiver, and going lighter would provide speed to corral Jackson.
Ultimately, the Ravens will still generate numbers advantages through scheme and the leverage of Jackson's legs. The only solution is simply beating blocks over and over, which the 49ers can do. They must do so enough to force passing situations.
2. When the Ravens pass
This is where things get fascinating.
The 49ers' pass rush is fantastic -- even with Dee Ford injured -- but the Ravens' line has been great in protection. That's especially true of left tackle Ronnie Stanley, who deserves All-Pro consideration. He's quieted some outstanding rushers, including Myles Garrett and Chandler Jones, and now he'll face the rookie wunderkind in Bosa.
Bosa may not trouble Stanley play after play, but San Francisco should have an advantage inside, where Buckner, Jones and sometimes Armstead will try to attack left guard Bradley Bozeman and center Patrick Mekari, the replacement for injured starter Matt Skura. The Niners' interior should threaten -- or at least create push in Jackson's face -- with regularity.
In coverage, the 49ers showed more man against the Packers last week but seem likely to lean on zone against the Ravens, keeping more eyes on Jackson's scrambling.
Jackson has diced up zones much of the season, especially over the middle, but the 49ers have a terrific zone-coverage linebacker in Fred Warner. The second-year man's ability to anticipate route combinations, feel routes behind him and move seamlessly between them is uncanny.
Warner is also speedy enough to serve as a QB spy when the 49ers do play man coverage, but containing Jackson's scrambles will fall just as much on the D-line. As they did last week against Rodgers, the 49ers' rushers must not go past Jackson, ideally rushing through blockers more often than around them, in order to keep him contained.
3. How much does Belichick respect Hopkins?
As we broke down in Monday's Film Study, the New England Patriots trusted Stephon Gilmore to handle Cowboys wideout Amari Cooper almost entirely on his own Sunday. Perhaps the weather contributed to the decision, but Bill Belichick clearly felt comfortable with the two on an island, and he was proven right.
Will Belichick show more respect for Houston Texans wideout DeAndre Hopkins?
Based on the coach's praise for Hopkins this week -- "You put NFL receiver in the dictionary, his picture is next to it," Belichick said -- the answer is likely yes.
The Patriots have not matched Gilmore exclusively on Hopkins in the past, instead mixing it up with a variety of looks, including Gilmore plus safety help at times. The approach hasn't stopped Hopkins from catching passes (15 grabs in the last two meetings), but it's limited big plays, holding Hopkins around 10 yards per catch.
Regardless of which cornerback is on Hopkins, expect Belichick to provide safety help regularly, not just by rolling one over the top but with a dedicated bracket.
That could free Gilmore to track Will Fuller, or Fuller could see a mix of Gilmore, Jason McCourty and Jonathan Jones. Due to injuries, the speedster has faced the Patriots just twice, and not since January of 2017. He's totaled only six catches for 47 yards in two meetings, which won't be enough on Sunday.
4. Spagnuolo's complexity aiding Chiefs
Despite so-so personnel, the Kansas City Chiefs' defense ranks 11th in yards per attempt allowed (6.48), 14th on third down (37.1 percent) and ninth in interception rate (2.5 percent). New coordinator Steve Spagnuolo deserves credit, having infused a defense that grew stale under Bob Sutton into an attacking unit with complexity to confuse quarterbacks.
Spagnuolo's preferred long-yardage, passing-downs coverage is a perfect example. It begins like Cover-2 and finishes like Cover-2, but involves a jarring rotation that can throw off quarterbacks even though they know it's coming.
Safeties Juan Thornhill (to the strong side) and Tyrann Mathieu (weak side) align in a 2-high look, with nickel back Rashad Fenton playing 6-8 yards off the slot receiver (to Thornhill's side). At the snap, Fenton drops to the deep half while Thornhill slides to the other deep half (Mathieu's initial side). Mathieu plays flat-footed, moving to the middle -- the normal spot for the middle linebacker in Cover-2 Tampa -- and reads the QB.
Two of Philip Rivers' four interceptions in Week 11 came against this coverage, one where Rivers' eyes led Mathieu to the ball, and another where Fenton's depth and speed let him cut off a deep post. Rivers surely saw this coverage weekly from Spagnuolo on tape, and yet it still caught him twice.
Oakland Raiders quarterback Derek Carr -- who threw two picks against Kansas City in Week 2 -- has plenty to be prepared for mentally.
5. Broncos' undrafted gem ready for encore
Speaking of Rivers, one of his interceptions -- plus a dropped pick -- in the Los Angeles Chargers' Week 5 loss to the Denver Broncos went to a little known linebacker who is quietly shining: Alexander Johnson.
A second-year undrafted player, Johnson made his NFL debut on defense as an injury replacement in Week 5. Despite some mental errors, he was terrific, collecting eight tackles (one for loss), the interception (in the end zone) and two passes defensed while showing excellent awareness in zone coverage.
Johnson has run with the opportunity since, continuing to impress in zone coverage but also standing out with physicality in run defense and as a blitzer. The latter area is especially important in Vic Fangio's scheme, which features many zone exchanges where an edge rusher drops and an inside linebacker rushes.
Rivers should see plenty of Johnson in the rematch on Sunday. The linebacker will be responsible for shrinking windows over the middle, and he'll likely be employed in blitzes to attack the Chargers' weak interior O-line.
--David DeChant (@DavidDeChant), Field Level Media