49ers-Rams 'TNF' takeaways: San Francisco's defense stifles Los Angeles offense in blowout

In the first major upset of the 2026 season, it was the San Francisco 49ers, not the Los Angeles Rams, who put on a show on Thursday night. 

Even undermanned, the 49ers took down their rival with one of the best performances any team has put forth against Los Angeles in a long time. Thanks to a dominating effort on defense and enough on offense from Brock Purdy and company, San Francisco shocked Sean McVay, Matthew Stafford and even Myles Garrett in his debut with his new team. 

And while Week 1 is often not indicative of how the full season will unfold, it's already clear those who wrote off the 49ers did so prematurely, and those who thought the Rams would coast through most matchups may want to think again. 

Key takeaway: San Francisco's defense can make the 49ers contenders no matter what

San Francisco's defense held Stafford, coming into the game as the reigning league MVP, in check, only allowing him to complete 15 of his 25 passes. They also picked off the future Hall of Famer — Stafford only threw eight interceptions all season last year. Stafford thew at least one touchdown pass in every game a season ago, but he finished Week 1 in 2026 without one. 

It was also the 49ers defense that set up their offense and helped lead to 24 straight points. A critical 4th-and-goal stop as Stafford came up short trying to punch the ball in himself and a touchdown following a fumble recovery combined to put the nails in the Rams' coffin. 

The highly powered Rams offense was only able to put up seven points, 15 first downs and 290 yards all game long. 

Week 1 caution: The Rams will wake up 

Despite struggling to find a rhythm in Australia, an offense led by Stafford — who surpassed 4,000 yards passing for the 10th time in his career in 2025 — Devante Adams and Puka Nacua will be dangerous eventually, even if it takes a week or so for them to get going. 

Garrett will make an impact on the defensive side of the ball. And so will Aaron Donald when he officially makes his return to game action. While the 49ers did show the Rams are beatable, the reverse could easily happen in the next matchup between the NFC West foes. 

Player of the Game: Fred Warner 

Purdy completed 25-of-34 passes for 205 yards and tossed three touchdowns. Mike Evans caught a touchdown in his first game as a 49er. Deebo Samuel had six receptions for 48 yards and a score. But the 49ers defense was the most valuable unit by far.