The San Francisco 49ers dominated the Cleveland Browns 31-3 on Monday night to stay undefeated, but it's what happened before the game that drew the ire of the Niners' Richard Sherman.

The veteran cornerback was annoyed with second-year Browns quarterback Baker Mayfield refusing to shake hands at the coin toss.

"What's amazing, and annoying, was him not shaking hands at the beginning," Sherman told NFL.com's Mike Silver. "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."

Mayfield, 24, acted as one of the Browns captain for the coin toss and didn't customarily shake the hand of Sherman or DeForest Buckner, two of San Francisco's representatives. Mayfield did slap hands with Niners tight end George Kittle.

"That can rub a lot of people the wrong way," Buckner said of the snub. "I guess it's part of his game. Oh well."

For Sherman, the lack of cordiality from Mayfield was motivation to try to humble the Heisman Trophy winner.

"Respect the game," Sherman said. "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."

Mayfield finished the game with 100 yards on 8-for-22 passing and a pair of interceptions.

One of the picks was made by Sherman.