The Detroit Lions vs. the San Francisco 49ers for the NFC championship is what everybody predicted when the season began. And by everybody, we mean nobody in their right minds.

The 49ers are not a surprise. This is the third year in a row they're playing for a trip to the Super Bowl, and their offense has more options than a multiple-choice test. The Lions, on the other hand, are the NFL's biggest surprise this season and, quite frankly, its best story. A team with some high-profile castoffs and seeming misfits has come together and energized a city starved for success.

The 49ers are the heavy favorites, but Detroit has been upending conventional wisdom all season long.

We asked our USA TODAY Sports NFL crew what they see as the key factors to watch in the game. Here's what they said:

Amon-Ra St. Brown has gone over 100 yards receiving in four of Detroit’s last six games and has had a TD catch in all but one of those games. How can San Francisco slow him down?

Jarrett Bell: By beating up his quarterback. Every great receiver needs somebody to throw him the football, as Gisele once reminded us. So, containing St. Brown begins with making life miserable for Jared Goff. And in San Francisco's scheme, getting pressure on the quarterback is not so reliant on blitzing, which helps on the back end. Oh, the back end. It will be interesting to see whether D-coordinator Steve Wilks decides to just stick Charvarius Ward on St. Brown, then work from there. And with the array of weapons in Detroit's offense, the chess match begs for the ability to mix and match the double coverage options across the board. Something to note: St. Brown averaged 7.4 catches and 82 yards in Detroit's five losses. But it's also true that in those five games, he scored all of one touchdown. So, he may get his, so to speak, but they need to blanket the guy in the red zone.

Chris Bumbaca: The 49ers D certainly looked as if it had taken a week off prior to the Packers game. Their next assignment isn’t much easier and St. Brown is a big reason why. But the Lions have plenty of other weapons in both the ground and passing games, and the Niners cannot be all-encompassed by St. Brown. Cornerback Ambry Thomas committed two pass interference penalties and was beaten in coverage several times, so making sure he’s not lined up on the other side of St. Brown is a good start for Steve Wilks’ crew.

Nate Davis: Maybe a touch of Bay Area fog would shade the “Sun God” … if only the Niners didn’t play in Silicon Valley. But the San Francisco D doesn’t need AI or even more processing speed to deal with St. Brown, good as he is. A unit that typically rushes only its front four consequently drops seven into coverage — and that means optimized ability to mug and re-route the All-Pro at the snap. And while he typically does stellar work over the middle, St. Brown isn’t usually contending with linebackers the caliber of Fred Warner and Dre Greenlaw, who are certainly capable of dissuading anyone from operating inside the numbers. Barring that? Maybe dial up a few extra blitzes — after all, if QB Jared Goff is on his back, St. Brown probably isn’t going to hurt you.

Tyler Dragon: Detroit’s biggest matchup advantage on offense is Amon-Ra St. Brown. The weakest link on the 49ers defense is their secondary. If I was the 49ers defensive coordinator, I would press St. Brown. Pressing St. Brown should make it more difficult for the wide receiver to get free releases, which in theory will provide the 49ers’ stout defensive front a little extra time to get after Jared Goff. San Francisco’s fierce pass rush covers up what is a leaky secondary. St. Brown has the edge over the 49ers cornerbacks, but the key for the 49ers is to make him take a little extra time getting open.

Lorenzo Reyes: This is a two-fold issue. St. Brown is so quick and shifty, especially off the line of scrimmage, that getting hands on him and jamming him at the line is key. The problem is that Detroit loves moving him all over the field, including having him line up in the slot. If San Francisco has one weakness on defense, it’s in the secondary. So it will be incumbent on the Niners edge rushers to get past Detroit’s tough offensive line and hurry Goff into quick throws. The problem there is that St. Brown is electric in the open field, so shading some help coverage will go a long way.

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Detroit’s defense has given up 400-plus yards in each of its first two playoff games. Now come the 49ers, who have no shortage of weapons offensively. McCaffrey. Kittle. Samuel (if he plays). Aiyuk. Etc. If the Lions can only shut down one playmaker, who do they choose and why?

Jarrett Bell: Christian McCaffrey. The dual threat that CMC brings in the rushing and passing games puts the "X" on his back. And with Brock Purdy prone to struggle at times, the 49ers simply need to run their offense through the star running back and likely NFL Offensive Player of the Year. What's so impressive about McCaffrey is the variety of ways that he can sting a defense. He can run with power and speed. As demonstrated against Green Bay, he can take a cloud-of-dust inside run and turn it into an explosive run that goes the long distance. Ditto for the passing game. And when it's tight near the goal line, McCaffrey's 21 touchdowns (tied for the NFL lead) this season tell quite the story. So, it's no secret that eliminating CMC is the top priority for the Lions defense. That's nothing new. The game will probably hinge on whether Detroit can accomplish that mission.

Chris Bumbaca: Christian McCaffrey doing Christian McCaffrey things these days is good for, what, a touchdown a game? Maybe two? So if the Lions could hypothetically contain McCaffrey to no significant production, they would certainly take that. The sentiment is the point here, though. If the Lions can somehow make the Niners one-dimensional through the air — McCaffrey is still a threat in that aspect, too — they put the pressure on Brock Purdy to make throws and give themselves a better chance of pulling off the upset.

Nate Davis: The Niners most definitely force opposing defenses into a pick-your-poison conundrum. But Samuel, assuming his shoulder and pain threshold allow him to play, might be the most toxic. His versatility as receiver, wingback, blocker and bulldozer is renowned. There’s also quite a correlation to his availability and San Francisco’s success. Of the Niners’ five losses this season, Samuel missed two with injury, barely played in another when he first banged up his shoulder, and rested for most of Week 18’s inconsequential defeat. The offense sputtered again in Saturday’s escape from the Green Bay Packers, when Samuel only posted for 33% of the snaps. One of two players ever with 4,000 receiving yards and 1,000 rushing yards over his first five NFL seasons, Samuel’s impact can’t be understated. (But if he’s inactive, Dan Campbell’s D should sell out to stifle RB Christian McCaffrey.)

Tyler Dragon: Deebo Samuel and Christian McCaffrey are San Francisco’s two best offensive weapons. They are equally as important because of the effect they have on the offense. If the Lions shut down both of them, they’ll likely be headed to Las Vegas. However, Samuel might be sidelined for this game due to a shoulder injury. So, naturally I’ll say McCaffrey. The 2023 rushing champion produced 2,023 yards from scrimmage and 18 touchdowns. Lions defensive coordinator Aaron Glenn will certainly gameplan to stop both Samuel and McCaffrey. But McCaffrey takes priority simply because Samuel will be playing at less than 100% or not playing at all.

Lorenzo Reyes: This has got to be Christian McCaffrey. A candidate for Offensive Player of the Year, frankly, your best hope is to limit him because shutting him down seems like a Herculean task. The problem is his versatility; despite his size, he’s powerful enough to take on a heavy batch of carries in between the tackles, but he can also slip out of the backfield and has excellent hands. His 12 targets in the divisional round against the Packers were a team high.

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The 49ers are in the NFC championship game for a third consecutive year and fourth time under Kyle Shanahan while this is the Lions’ first appearance since 1991. Is the experience imbalance overrated?

Jarrett Bell: Maybe. As this season progressed, I'm probably not the only one who felt that the Lions were like a year away from being on the verge of reaching the Super Bowl. They've been building something special under Dan Campbell. And we've seen teams over the years take their steps to championship glory. Then again, we've also seen teams arrive early, so to speak. That might be this Lions team, driven to prove they are a NOW team. I was at Candlestick Park in the early '90s when another up-and-coming team arrived early and shocked the 49ers in the NFC title game. Can the Lions mimic those old (and certainly not current) Dallas Cowboys? By the same token, the championship game experience the 49ers have gained surely counts for something. I'm thinking guys like Fred Warner and George Kittle are sick of "experiencing" title game defeats and might draw on some extra resolve because of it.

Chris Bumbaca: Overrated can be a strong word. Probably not. But it’s not even in the top 30 reasons why the Niners could beat the Lions on Sunday. I’d say having home-field advantage is more of a difference-maker for the Niners. Detroit played only one-third of its games outdoors. QB Jared Goff is not nearly as productive in the elements than in the friendly confines of Ford Field. But it will be a homecoming for the northern California native.

Nate Davis: In a word, “yes,” most definitely overrated. Last year, Philadelphia Eagles QB Jalen Hurts nearly won the Super Bowl in his first extensive playoff drive. Same deal for the Los Angeles Rams’ Matthew Stafford, seasoned as he was in the regular season, and a greenish Cincinnati Bengals squad during the 2021 playoffs. Even former Niners QB Jimmy Garoppolo, who played in his first postseason games during the 2019 postseason, reached Super Bowl 54 and nearly won it … vanquishing “experienced” counterparts like Kirk Cousins and Aaron Rodgers along the way. And we’ve certainly witnessed playoff familiarity lead to a pucker factor in places where the expectations are astronomical … right, Dak? Don’t be remotely shocked if the 49ers, near-perennial NFC title game participants of late but never a Super Bowl champion, blink against a Lions team that doesn’t seem to be feeling any pain … or pressure.

Tyler Dragon: The experience imbalance isn’t overrated but it’s definitely something to monitor. The 49ers came into the season with Super Bowl aspirations. They were the best team in the NFC all year. The Lions entered the season trying to gain relevance and rid themselves of a losing reputation. The Lions are playing with house money because not many expected them to reach the NFC championship game. Will there be jitters to start? Sure. But nerves should dissipate for the Lions. It’s still just a football game even though the stakes are higher.

Lorenzo Reyes: This is a complicated question to answer because teams are so wildly different. Experience can be a good thing, certainly. But Detroit has something akin to experience. The Lions franchise has been suffering in a purgatory of mediocrity and this version of the team seems to be feeding off of the city’s energy. Indeed, Lions fans have been everywhere this season, taking over opposing stadiums. In an NFC championship game in Santa Clara, that will be a taller task. But inexperience, if channeled properly, in a way that allows players to feel free and loose, free of expectation — that can be a very dangerous weapon. Dan Campbell is just the type of coach to draw that out of this team. Plus, quarterback Jared Goff, a captain and team leader, has started in a Super Bowl.

This article originally appeared on USA TODAY: Lions-49ers: McCaffrey, Jared Goff's targets amid NFC title questions