What We Learned From Week 16 in the N.F.L.

For most of us, it’s the crescendo of the holiday season, but for the NFL, it’s do-or-die time. Two scrappy underdogs, the Lions and Seahawks, saw their playoff chances shrink with painful losses, while the Panthers extended their hopes for at least another week.

The Lions’ recent success may have been an illusion.

The Detroit Lions season was shaping up to be a Cinderella story. After a 1-6 start, the Lions had battled back with a 6-1 run to get to .500 heading into Christmas weekend. Though they were still a long shot for the playoffs, the Lions were rolling, and they controlled their destiny. But it all came crashing down under the weight of a desperate Carolina Panthers’ run game.

The Panthers, barely clinging to playoff hopes themselves, mashed the Lions up front. It was a four-quarter stomping, but the Panthers did a majority of their work in the first half. Led by Chuba Hubbard and D’Onta Foreman, the Panthers rattled off 240 yards on 22 carries in the first two quarters alone, an effort that put them up 24-7 at the half.

The Lions’ edge defenders and linebackers had a particularly rough day. On the first play of the game, the Panthers set up a misdirection play. The entire line blocked to the right side, and Hubbard took his first step that way, but then he cut back the other way. With one blocker coming back across the formation, Hubbard ran from right to left, away from the direction the Lions defense had been suckered into going. Hubbard raced to a 30-yard gain, an omen of what was to come.

Midway through the second quarter, tied at 7 with 9:40 left, Panthers quarterback Sam Darnold held the ball on an option play for a touchdown. The Panthers called a zone read on the goal line, putting Lions edge defender Romeo Okwara in a bind between the running back and the quarterback. Okwara crashed on the running back, freeing Darnold to trot into the end zone as the Lions’ linebackers got stuck inside playing the fake handoff.

A lack of run defense and discipline killed a Lions team that was built on running the ball and doing all the little things right. They’re normally a sound team, if a bit short of talent on both sides of the ball, but they erred on Christmas Eve, a performance that may well dash their chances of playing postseason ball. The Upshot now has the Lions with just a 17 percent chance to make the playoffs.

The Vikings need to learn how to win big.

The Minnesota Vikings had already locked up a playoff spot and the N.F.C. North title, but a dramatic win over the Giants moved them to 12-3. Kicker Greg Joseph finished off the affair as time expired, draining a 61-yard field goal to give the Vikings the 27-24 victory. The narrow win was a perfect encapsulation of a Vikings team that somehow escapes with victories despite never dominating its opponents.

In games decided by a single possession — 8 points or fewer — the Vikings are now 11-0 this season. They have beaten just one opponent by more than 8 points, and that came in Week 1 against the Green Bay Packers. Those 11 close wins include a bizarre final two minutes against the Bills that featured Justin Jefferson’s one-handed catch on fourth-and-18; the biggest comeback in N.F.L. history against a Jeff Saturday-coached Colts team; and now a career-long field goal for Joseph that was also the longest ever for the Vikings. The last might be the most impressive considering Minnesota’s history of kicking woes since, well, as long as anyone can remember. This year has been shockingly kind to the Vikings.

Relying on tight wins is dicey in the playoffs, though. Competent teams keep games close and the fortunate ones win them, but great teams find ways to dominate their opponents. The Vikings haven’t done that. Instead, they were slammed in their three losses to the Eagles, Cowboys and Lions by a combined score of 98-33. It’s obviously great to win football games, but close-game wins are generally not sustainable, and the Vikings haven’t proved they can win big.

The Vikings might need to find another gear to be a serious contender, a gear more convincing than a 3-point home win over the Giants.

Kansas City’s success may not be all about its offense.

Nobody will mistake Kansas City for a defensive team. Patrick Mahomes, Travis Kelce and Andy Reid run the show, and all the defense has to do is hold the other team to fewer than 30 points in most weeks. But Sunday’s win over the hungry Seattle Seahawks was different. Kansas City’s offense put up a respectable 24 points, but it was the defense that really did the job, holding Seattle to 10 points and perhaps giving the team an extra bit of confidence heading into the postseason.

Kansas City had held only one other opponent to 10 points this season. That was in a Week 11 win over a Rams team quarterbacked by backup Bryce Perkins and missing wide receiver Cooper Kupp. That hardly compares to smothering the Seahawks, whose offense has been rolling for most of the season behind Geno Smith, a Pro Bowl quarterback who has DK Metcalf at his side.

It was a collective effort from the Kansas City defense, with a focus on stopping the Seahawks’ passing game. Up front, Chris Jones led a pass-rushing onslaught that garnered two sacks of Smith and seven quarterback hits. Rookie defensive end George Karlaftis popped for his biggest moment of the season, earning a well-timed third-down sack deep in Seahawks territory after beating Seattle rookie tackle Abraham Lucas around the edge. Smith was under duress all day and was not getting the pockets he had been used to.

Kansas City’s physicality and variety of zone coverages played well against the Seahawks’ receivers. Metcalf still produced a solid seven catches for 81 yards, but it wasn’t enough to carry the offense. Smith seemed rattled by the heavy pressure and mix of coverages, leading him to take more checkdowns and short throws than he might have otherwise. Kansas City’s second- and third-level defenders did an excellent job rallying to tackle on those short throws, leaving the Seahawks with a nickel-and-dime approach that didn’t produce enough coins to pay for a win.

It must be said that the Seahawks were without wide receiver Tyler Lockett, who surely would have made this game more difficult for Kansas City. But this was still Kansas City’s most convincing defensive performance, and it could not have come at a better time. If its defense can inch closer to average, as opposed to the below-average unit it has been for most of the season, Kansas City might again be the team to watch in January.

Around the N.F.L.

Vikings 27, Giants 24

Bengals 22, Patriots 18

Bills 35, Bears 13

Saints 17, Browns 10

Kansas City 24, Seahawks 10

Panthers 37, Lions 23

Ravens 17, Falcons 9

Texans 19, Titans 14