FULL BOXSCORE

1. Mason replaces McCaffrey during his absence. Christian McCaffrey‘s appearance on the inactive list came as a surprise, considering he was already listed as questionable with a calf and Achilles ailment before Monday, and many wondered how the 49ers would adjust without him against a Jets team known for its cheap defense. Ultimately, we needn’t have worried, because if there’s any coach who’s going to maximize production from lesser-known running backs, it’s Kyle Shanahan, who Jordan Mason in his offense and watched him blossom. Mason finished with 147 yards and a touchdown on 28 carries, leading a 49ers offense that used the ground game to gain a dominant advantage in time of possession (38:40 to 21:20), and peppered New York’s defense with a collection of Brock Purdy passes to six different targets. Make no mistake: The star of the night was Mason, the latest running back to rise from irrelevance to prominence, joining the likes of Raheem Mostert, Elijah Mitchell, Jeff Wilson, Matt Breida and others, even if only for one night.
2. The Jets defense collapses. For most of the Robert Saleh era, New York has hung its hat on its defense. It’s been the Jets’ savior when they’ve been without a legitimate quarterback. But for the first time in recent memory, the Jets’ defense failed to show up on Monday night, allowing the 49ers to muster 401 yards of offense and string together an astonishing number of long drives. Five of San Francisco’s nine possessions lasted nine plays or longer, and four of those went for at least 70 yards. The most surprising detail here? The 49ers didn’t need to convert much on third down to keep things going, finishing 6 of 13. The 49ers schemed better than the Jets, looked to have a step ahead of New York from the second quarter onward, and executed better than the Jets, who struggled to mount much of a pass rush (10 total pressures) without a holdout Haason Reddick and rarely had an answer to whatever Shanahan came up with.
3. Kyle Shanahan starts 2024 strong. If the time-of-possession advantage isn’t enough of a story, just watch any of the 49ers’ eight consecutive scoring drives for proof of just how deep Shanahan was in the bag Monday night. The expert play-caller took complete control of the game from San Francisco’s third possession onward, mixing in a number of different run concepts while also causing headaches for New York’s pass defense. The highlight was a sight for football nerds to behold. After Purdy caught a wide-open Kyle Juszczyk Shanahan raced down the sideline and chose a wheel route for the fullback, who left the backfield through the B gap and found a soft spot between defenders for a 34-yard reception down the left sideline midway through the third quarter. By this point, it was clear the Jets would have no answer for Shanahan, whose mastery of his own offense was on full display, helping the 49ers cruise to an emphatic season-opening victory.
4. Rodgers provides a preview of what the Jets could be. The fourth game of the season is supposed to bring bad luck for Aaron Rodgerswho saw his 2023 season end on the fourth snap and saw Breece Hall fumble away possession on their fourth snap of Monday night’s game. Lesser teams might struggle to overcome an early setback like this, but not Rodgers, who immediately recovered and led a well-balanced 12-play, 70-yard drive that included two third-down conversions on completions to Garrett Wilson and culminated in a touchdown run from three yards out by Hall. The march was so impressive that social media was abuzz with claims that it was the best Jets lineup of the past 10 years, if not longer. Hyperbole aside, it was certainly impressive and suggested that we might be in for a cracker between two heavyweights. Ultimately, we learned that it was merely a glimpse of what the Jets’ offense could look like with Rodgers at the helm, as a lack of execution (two consecutive three-and-outs followed) hurt their ability to control possession, and by the time they had a legitimate chance to put something together, a 16-point deficit threw a wrench in whatever offensive coordinator Nathaniel Hackett had in mind for the offense. Still, it was a nice taste of what Rodgers — who caught just 21 passes Monday night — could produce with the Jets. We’ll see if that happens more often in the coming weeks.
5. New York has its benchmark. The Jets started 2023 with an extreme amount of fanfare, only to see it evaporate after four plays. This time around, Rodgers breezed through the game without incident, and while he did throw an interception in the second half, he still gave Jets fans a taste of what could be a delicious dessert. One thing is for sure, though: The Jets need to improve their defense, once their calling card that didn’t show up on Monday night. Reddick’s absence was noticeable, and perhaps that result will prompt action regarding his contract-related holdout. Even if that doesn’t happen, the Jets now know what it’s like to take their talents and pit them against an elite NFL team — and they’ve learned that they’re not there yet. Fortunately, Week 1 is the best time of the season to learn that lesson.

Next Gen Game Stats: Niners left tackle Trent Williams has not allowed a single QB pressure on 33 pass-blocking snaps. This is his first game since Week 2 of the 2022 season without allowing pressure on at least 14 pass-blocking snaps.

NFL Research: Shanahan’s 49ers played keep-away successfully on Monday night, dominating the time of possession from 38:40 to 21:20. The Jets’ 21:20 of possession was the lowest mark in a game in Aaron Rodgers’ career.