The San Francisco 49ers' run defense is usually a pillar of strength. It was anything but on Sunday as the Niners fell to their first defeat of the season at the hands of the Cleveland Browns.

San Francisco lost 19-17 in Cleveland as kicker Jake Moody missed a would-be game-winning field goal from 41 yards. There were a host of other contributing factors to the upset, however, among them an unexpected drop off against the run.

The Niners gave up 160 yards on the ground, marking the second time in the last three games they have allowed 100 yards rushing. They did so only four times across the regular season in 2022.

It was a clear area of disappointment for head coach Kyle Shanahan, who pinpointed the run defense on the Browns' final two field goal drives, on which Cleveland gained 66 yards on the ground, as a specific area of frustration as the 49ers' struggles in that area took much of the pressure off Cleveland quarterback P.J. Walker.

"Yeah, I was disappointed in it," Shanahan said of the run defense on his Monday conference call. 

"I'm not sure the exact stat compared to the others, but if I had to guess it was our most missed tackles on the year. I thought they got our edges way too much, just blocking down on our D-Ends and getting around. 

"We played a lot more two-shell defense and when you play two-shell defense you're a little bit behind in the run game. But we've been able to stop guys pretty good in that way. When they got our ends and we didn't get our safeties downhill, they bled us out too much. And when you add on a couple of those missed tackles and everything, it was way too much. 

"Especially when you've got a quarterback coming in who hasn't started yet the best way to make that guy uncomfortable is to take away the run game and with 160 yards in that, we obviously didn't. That was disappointing, especially on those last two drives."

San Francisco's slip-up in Cleveland was not as costly as it could have been, with the Philadelphia Eagles also suffering a surprise defeat to the New York Jets. The Niners, Eagles and Detroit Lions are in a three-way tie atop the NFC at 5-1.

But the 49ers can ill-afford an in-conference loss to a 2-4 Minnesota Vikings team on Monday Night Football in Week 7. 

The Vikings' run game ranks 22nd in Expected Points Added per play and, with linebacker Dre Greenlaw set to return from a hamstring injury, the Niners have little excuse not to get back to their previous standards in defending the ground game as they look to respond to their first adversity of the season.

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