Video from inside the stadium shows a violent brawl that broke out between a group of home fans in the stands. The footage captured men and women trading blows.
MORE: Fight breaks out at Levi's Stadium during 49ers-Broncos preseason game
One of the men in the video appears to pull a woman down the bleachers by her hair while holding a beer. A security guard eventually arrived and broke up the fight.
It's not clear what prompted the violence or if anybody was arrested.
Video posted on social media shows another violent fight in the stands after the game, where 49ers and Giants fans appear to throw punches at each other.
MORE: Man describes being stabbed during massive fight at Levi's Stadium soccer game
Meanwhile, New York's offense never managed to get going against San Francisco's tenacious defense. The 49ers won 30-12.
This is the third instance of fights being caught on camera at Levi's Stadium this year.
In July, a fight broke out in the stands during a soccer match and a man was stabbed and critically injured.
Then another brawl broke out in the stands in a preseason game between the 49ers and the Denver Broncos.