The New York Mets and Atlanta Braves’ National League East rivalry was carried on off the field as fans brawled with each other on Saturday night.

The fight occurred in the seats down the first-base line. Video posted on Twitter showed a man in a Braves jersey swinging over a Citi Field security guard trying to punch two other men in Jacob deGrom jerseys.

After the Braves fan failed to really connect on a punch, one of the Mets fans came back swinging and appeared to knock out the man. One person could be heard yelling, "F--- him up!"

CLICK HERE FOR MORE SPORTS COVERAGE ON FOXNEWS.COM

WARNING: EXPLICIT LANGUAGE

It’s unclear what started the brouhaha.

The Mets beat the Braves in both games of their doubleheader on Saturday.

Max Scherzer struck out 11 batters in the second game of the doubleheader to lead New York to a 6-2 victory in the evening game. In the afternoon game, Francisco Lindor added three RBIs and the Mets won the game, 8-5.

"They’re a great team, great lineup," Scherzer said of the Braves. "For us to show up and bring the energy and go out there and beat them, that’s great. It’s great to get these wins, but it’s not over yet. We know how good they can play, and they can get hot."

The Mets took a 5.5-game lead in the NL East and improved to 69-39. They are 30 games over .500 for the first time since finishing 97-65 in 2006.

Mets manager Buck Showalter picked up his 1,620th win to move past Ralph Houk for 20th on the all-time wins list.

The Associated Press contributed to this report.