"Who? Who?" Pierce repeated Thursday when asked about Smith's comments.
Asked again, Pierce said, "Who? Exactly. Who? Who are we talking about right now? Exactly. Who are we talking about? We are talking about nothing."
Pierce fired the first shot in the East River Rivalry this summer when he said it was time for the Nets to start running New York City. The war of words between the two teams only escalated from there.
"I just look at him as a bitter person just getting out of Boston. He doesn't really know what New York is all about. He's been playing in Boston his whole career," Smith responded to ESPN New York.
Smith added: "He just knows, just know that his words have consequences and he's going to have to pay for them."
Pierce spent the first 15 seasons of his career with the Celtics before being traded to the Nets.
"Everybody knows how much I disliked the Knicks when I was with the Celtics, but I think it's grown to another level," Pierce said on ESPN New York 98.7 FM's "The Michael Kay Show." "I think it's time for the Nets to start running this city."