You didn’t have to be at Levi’s Stadium on Sunday to feel the shock as Jimmy Garoppolo was carted off the field in the first quarter against the Miami Dolphins. The season had mostly been on an upward trajectory for the San Francisco 49ers since Garoppolo took over for an injured Trey Lance in Week 2. With Garoppolo, who already knew the playbook, under center and most of the 49ers’ endless offensive weapons healthy and productive, San Francisco were suddenly a team to reckon with. When they traded for Christian McCaffrey in October, they became a legitimate Super Bowl contender.

But with Lance out for the season and Garoppolo suffering what would later be revealed to be a broken foot, the chances of victory suddenly seemed grim. The Niners defense is great, the league’s best in fact, but who was going to make sure this team scored points? Enter Brock Purdy, the Iowa State alum who the 49ers took with the last pick of the 2022 draft. Yep, Purdy is the most recent Mr Irrelevant.

It couldn’t have been a more daunting situation for the rookie. The Dolphins, with their high-octane offense, were ahead 7-3 after Tua Tagovailoa hit former 49er Trent Sherfield up the seam for a 75-yard touchdown on the first play from scrimmage. Tensions were high: Kyle Shanahan was facing his former protege Mike McDaniel, now head coach of the resurgent Dolphins. McDaniel now has several former 49ers on his roster. It was a huge game for both teams in terms of playoff standings and personal victories.

Related: NFL roundup: Burrow and Bengals beat Chiefs again; Jackson injures knee

But the tension didn’t seem to extend to Purdy, who waltzed in and led the 49ers on a touchdown drive and a 10-7 lead: they would not trail in the game again. The drive heavily featured McCaffrey but Purdy capped it off by completing a short pass to fullback Kyle Juszczyk. Purdy was stiff and tentative at first but gained confidence and poise as the game went on. Another well-executed drive by Purdy ended with a touchdown pass to McCaffrey and gave the Niners a 17-10 half-time lead. In the second half, Purdy hit more strikes up the middle and utilized more play action. He wasn’t perfect but it’s hard to imagine a third-stringer, who usually practices with the scout team, performing better in his situation. Purdy finished with 210 passing yards, two passing touchdowns and an interception. The 49ers won 33-17 and maintained their lead in the NFC West.

It’s no wonder Purdy was so confident. Any 49ers starting quarterback is instantly thrust into an almost ideal situation. No NFL team offers such a collection of offensive playmakers at all levels of the field, not to mention an elite left tackle in Trent Williams.

Purdy is raw, but not that raw. He was a four-year starter at Iowa State and passed for 12,170 yards and 81 touchdowns. With that experience under his belt, Malcolm Gladwell may even consider Purdy a quarterbacking expert.

Of course, Purdy’s confidence was aided by witnessing his team’s ridiculously talented defense rattle Tagovailoa all game. Nick Bosa sacked the poor Dolphins quarterback three times, and leads the NFL with 14.5 on the season. And when the defense wasn’t pressuring Tagovailoa physically, its mere threat seemed to unsettle him. Aside from Tagovailoa’s opening touchdown, and a later strike to Tyreek Hill, he was uncharacteristically off target the whole game.

The postgame smiles were wide from 49ers brass after such an emotional win, but it wasn’t all rainbows and sunshine. Shanahan announced that Garoppolo needs to undergo surgery that will end his season.

That leads us back to Purdy, who will now need to be more than a one-game wonder. He is suddenly the likely 49ers starter for the rest of the season. Next up is another formidable challenge: the Tampa Bay Buccaneers and Tom Brady. “He’s been playing football longer than I’ve been alive,” the 22-year-old Purdy said of Brady, 45. “Having the first start against the GOAT is pretty cool. I’ve just got to do my thing, be efficient and play football”.

If he can be as efficient as he was against Miami – and get a little help from his offensive weapons and defensive friends – there’s no reason the 49ers can’t continue to notch wins, even if a Super Bowl is now almost certainly out of the question for San Francisco.

49ers linebacker Fred Warner agrees. Referencing Purdy’s work on the scout team, Warner said: “He’s played against the best defense in the league for the past 13 weeks. He’ll be fine.”

The quarterback injuries have been tough for an excellent Niners team that will almost certainly have to wait for next season to mount a Super Bowl challenges. But for a moment, let’s appreciate a Sunday fairytale. For all the underdogs out there and anyone who’s ever felt irrelevant, congratulations. You have a new quarterback to root for.

MVP of the week

Joe Burrow, quarterback, Cincinnati Bengals. If the Bengals and Kansas City Chiefs are going toe-to-toe, there’s a decent shot Burrow ends up in this section. Burrow and company continued their ownership of the Chiefs, winning their third straight against KC. This one was by the same score as the last season’s AFC Championship game: 27-24.

Burrow played high-level, clean ball, completing 25-of-31 passes for 286 yards and two touchdowns. He also set the tone by scoring the game’s first touchdown with his legs. The Bengals got off to a shaky start this season, and appeared to be in a Super Bowl slump, but Burrow has elevated his game and shown once again how he can churn out clutch moments with the best of them.

Video of the week

When it mattered most, with the Washington Commanders down 20-13 to the New York Giants with under two minutes left, Josh Doctson turned a great catch into an incredible display of a wideout dominating in space. Doctson’s touchdown led to overtime, which ended in 20-20 tie. The Commanders now have a 70% chance of making the playoffs, according to FiveThirtyEight.

Quote of the week

Commanders offensive tackle Charles Leno Jr had an interesting assessment of playing to a tie that I present without comment.

Stat of the week

The Denver Broncos scored fewer than 17 points for the 10^th time this season. Another week, another situation where the Broncos’ elite defense should fly first-class and make their pulseless offense take a bus home with a bunch of crying babies. The latest example showcased a wildly overpaid Russell Wilson sputtering his offense to exactly nine points. No touchdowns, three field goals. And they wasted a valiant effort by the defense, losing 10-9 to the Baltimore Ravens, who lost Lamar Jackson early in the game to injury (he is expected to return later this season). The 3-9 Broncos have only scored 14 touchdowns on the season heading into Week 14. Although Wilson was a solid 17-22 passing, he led a Broncos offense that was just 2-12 on third down and made zero trips into the Red Zone. Just an utter embarrassment.

Elsewhere around the league

• Jalen Hurts gave his MVP campaign (another) boost on Sunday with a dominating performance in the Philadelphia Eagles’ 35-10 walloping of the Tennessee Titans. Hurts threw for 380 yards and three touchdowns and added a score on the ground. Two of those touchdowns were to former Titan AJ Brown, who reminded Tennessee how idiotic they were to trade him away. And the Eagles defense made Derrick Henry a complete non-factor (13 touches, 38 yards). The Eagles’ 11-1 record is a testament to what a complete roster this team fields.

• The Detroit Lions, arguably the NFL’s hottest team, put a beatdown on the Jacksonville Jaguars, winning 40-14. It was another masterly performance by the offense, who scored on all eight of their meaningful possessions (four touchdowns, four field goals). The Lions have now won four of their last five and sit at a respectable 5-7. “This is a game that can catapult us through the rest of December,” Lions coach Dan Campbell said. The Lions are still 2.5 games behind in the playoff race, with the Minnesota Vikings and New York Jets on the docket the next two weeks. Playoffs or not, Campbell has completely shifted the culture and made the Lions something they haven’t been in decades: an entertaining watch.

• For much of the Packers-Bears tilt in Chicago, it appeared that Aaron Rodgers’ possible last start as a Packer would be his first loss to the Bears in four years. Justin Fields was the better quarterback in the first half. But Rodgers’ first dagger fell when he hit rookie wideout Christian Watson for a 14-yard score on fourth-down with 23 seconds left in the first half. The Packers dominated the rest of the game, outscoring Chicago 18-3 in the second half. The 28-19 win was Green Bay’s eighth straight against Chicago and the franchise’s 787^th win, the most in NFL history.

• This was the NFL’s annual My Cause My Cleats week, when players get a reprieve from the league’s militant uniform policy. The causes – from combatting sleep-related infant deaths to ending gun violence to allowing women the right to choose – make for a powerful collection. But I urge the NFL to spread this platform throughout the season, so we can delve deeper into each player’s relationship to their selected cause. The players and their causes deserve much more attention.

• The Cleveland Browns defeated the hapless Houston Texans 27-14 thanks to a fumble returned for a touchdown, a punt returned for a touchdown and a pick six. Deshaun Watson, who has $184m left on his fully guaranteed contract, was 12-of-22 for 122 yards and an interception in his Browns debut.