TMZ obtained this video of the first moment things got heated Saturday night inside Chrysler Hall in Norfolk, VA -- almost immediately after Jerry hit the stage, one demonstrator stands up, and starts yelling, "Free Gaza!"

The solo protester also shouted and pointed at audience members, and said they should be ashamed of themselves.

As most of the crowd began booing, another man jumped up and grabbed the protester, wrestling with him and putting him into a headlock.

Security guards quickly responded and broke up the scuffle, escorting the demonstrator out of the venue -- it all created a scene that seemed familiar to the audience, because they started chanting, "Jerry, Jerry, Jerry!!!"

Sweet double entendre ... and RIP Springer.

As for Seinfeld ... he was cool as a cucumber throughout, especially when the fight broke out. He added some humor, telling the crowd ... "I love a little Jew hate to spice up the show."

According to eyewitnesses, Jerry told everyone not to boo the man because he had every right to protest -- and there were more agitators through the night.

We're told about 8 demonstrators disrupted Jerry's 1.5-hour show – but each time security led the people away without any trouble.

And Jerry never once got rattled. He took it all in stride and completed his performance to a standing ovation.