Mayhem at a 2011 preseason game between the San Francisco 49ers and Oakland Raiders had put what is typically referred to as The Battle Of The Bay on hold until this Sunday, when the Raiders ate the Niners' lunch, 24-13. This year, things were reportedly less violent in the stands, but as the video below shows, not everyone could behave.

Three people ended up in serious condition at SF General Hospital following a brawl-filled game at Candlestick in August, 2011. As a result, the 11-year run of preseason games between the 49ers and Raiders ended, and the teams managed to avoid each other during the regular season, as well.

So, police and security staff were reportedly on high alert Sunday at the Oakland Coliseum, when the two teams met for the first time since then. A typical home Raiders game sees 10 arrests, police say, and detentions this game were more than doubled, with 20 confirmed arrests and 10-12 others pending due to paperwork delays, CBS5 reports.

But, still, Assistant Sheriff Casey Nice characterized the misbehavior at the game to the Ex as "no different than any other game," and a Chron report described the game as a "mostly convivial gathering."

But, if the video below is to be believed, all was not peaceful at the game. Punches are thrown, drinks are tossed (aren't those things really expensive?), and one fan nearly takes a header down the stadium stairs before several nearly-identical cops step in to end the brawl, which I'm sure was over something really reasonable and important.

Related: Daisy Does the Niners: Kaepernick Hands Oakland 24-13 Win