The San Francisco 49ers didn't just get after Baker Mayfield on the field Monday night. They took him apart off it as well.

Niners defensive back Richard Sherman said after the game that the Browns quarterback refused to shake hands during the coin toss before the game.

"What's amazing, and annoying, was him not shaking hands at the beginning," Sherman said, according to NFL.com. "That's some college s---. It's ridiculous. We're all trying to get psyched up, but shaking hands with your opponent -- that's NFL etiquette. And when you pull bush league stuff, that's disrespectful to the game. And believe me, that's gonna get us fired up."

San Francisco defensive end Nick Bosa had his own retaliation on Mayfield. After harassing the QB into an intentional grounding call, he pretended to plant a flag -- mocking Mayfield's planting an Oklahoma flag at Ohio Stadium in a 2017 game against Bosa's Buckeyes.

"I think everybody knows what that was for," Bosa said. "I just wanted to get payback. He had it coming."

Sherman got his payback too, intercepting Mayfield on the Browns' second possession. After the 49ers coasted to a 31-3 win, Sherman was still surprised by Mayfield's pregame snub.

"Respect the game," Sherman said, according to NFL.com. "You can have rivals, but pay your respect in that moment -- especially when you're young.

"He hasn't earned anything in this league. How many games has he won? He's acting like he was the MVP last year. If [Patrick] Mahomes did that, it would be one thing. But he would never do that, because he has too much respect for the game.

"And when you see a guy who doesn't? You humble him every chance you get. Because eventually, he will have respect for the league -- or he'll be out of it."

Interestingly, the brash Mayfield has been on the other side of the snub. Before a 2017 Oklahoma-Kansas game, Jayhawks captains refused to shake Mayfield's hand during the coin toss.