The Rams, meanwhile, followed that shocking collapse with a dominant win over Arizona and then narrowly avoided an even bigger collapse, pulling out a thriller over the Buccaneers.
Now, with a trip to the Super Bowl on the line, they meet again. Here are the key areas for both teams in their third matchup.
When the 49ers have the ball...
When I previewed the Week 18 meeting, I noted that Jimmy Garoppolo needed to get the ball out fast to beat a dangerous Rams pass rush. Three weeks later, that still holds true. In the Week 10 win, Garoppolo took just 2.06 seconds to throw on average, his fastest this season. In Week 18, tasked with leading a big comeback, Garoppolo averaged 2.49 seconds to throw, still his fifth-fastest out of 18 games this season, including playoffs. This season, Garoppolo has averaged under 2.6 seconds to throw in seven games; the 49ers have posted a 6-1 record in those contests.
Jimmy Garoppolo vs Rams This Season
2.7 Seconds or Less to Throw
Over 2.7 Seconds to Throw
It also helps Garoppolo to get the ball out early because his receivers are terrific at turning quick, short throws into longer gains. The 49ers averaged 6.6 yards after the catch this season, tops in the league, and that number actually went up to 6.8 in the two games against the Rams. In the Week 18 matchup, the Rams defense missed nine tackles on pass plays, their most all season. In Week 10, they missed eight such tackles, their second-most all season. Can you sense a trend? It's incumbent upon Garoppolo to get the ball to his playmakers.
I'll also be interested to see how Garoppolo handles the blitz and if the Rams bring more blitzes. In the Week 18 game, when Garoppolo had much more to do than in Week 10, he struggled when Los Angeles brought at least five pass-rushers.
Jimmy Garoppolo vs Rams in Week 18
Yards per attempt
When the Rams have the ball...
On paper, the 49ers are the perfect foil to Matthew Stafford and the rest of the Rams' offense. Stafford thrives when opponents blitz. But the 49ers blitzed on just 21.7 percent of opponents' dropbacks this season, the eighth-lowest rate in the league, and that number has actually dropped to just over 19 percent in the postseason. In the two meetings with the Rams this season, San Francisco blitzed on just 12.3 percent of Stafford's dropbacks.
On the rare occurrences he was blitzed, Stafford made the 49ers pay.
Matthew Stafford vs 49ers This Season
Yards per attempt
I'd be shocked if the 49ers blitz more than just a handful of time on Sunday. They really don't need to, and that's what makes them so good. This regular season, when the 49ers did not blitz, they still pressured opposing quarterbacks on 30.4 percent of their dropbacks second-best in the NFL.
Stafford does have a tendency to do too much in these scenarios: When not blitzed this season, Stafford's average pass traveled 8.5 yards downfield, the fourth-highest number in the NFL. Of his four non-blitz interceptions against the 49ers, three were ill-advised deep balls thrown at least 20 yards downfield, like this one:
Stafford is a gunslinger by nature. The mentality that produces mistakes like the one above also produces game-winning moments like the one last week:
Give Stafford credit: After tying Trevor Lawrence for the NFL lead with 17 interceptions in the regular season, he has not thrown a pick -- and has thrown just one interceptable pass according to Pro Football Focus -- in the playoffs. On Sunday, the 49ers will sit back in coverage and hope he makes the same risky throws that cost the Rams both regular-season meetings. If he can avoid that, the Rams should be set up for success.