Chris Rock Shuts Down 'F*** Will Smith' Fan in Boston Audience

Chris Rock's getting rowdy support from fans after the Oscars slap in the form of at least one person cussing at Will Smith, but the comedian isn't having it ... and Thursday night he quickly defused the situation.

Chris had his 2nd show at Boston's Wilbur Theater briefly interrupted when someone in the crowd shouted out, "F*** Will Smith" -- and Chris heard it immediately, repeatedly saying ... "No, no no" until the chant stopped.

Security reportedly tossed hecklers out left and right, whether they were supporting Chris or not. One kicked-out fan told the New York Post, "All we did was interact and respond to the comedian ... They are so afraid that someone is going to say something that they kicked us out before we could."

Chris did eventually crack a joke about the situation -- reacting to one heckler with, "Is that the Oscars security?"

As we reported, Chris kicked off his "Ego Death" comedy tour at the Wilbur Wednesday night, and briefly addressed the Oscars slap from Will Smith, joking "How was your weekend?"

He told the audience he was still processing what happened and wasn't ready to fully address it.