J.R. Smith -- Barnes vs. Fisher Rematch Would Be a Good Fight

If Matt Barnes and Derek Fisher decide to settle their beef with one final UFC-style fight -- J.R. Smith wants a ticket ... telling TMZ Sports, "I would love to see that."

Smith even did some fight analysis ... breaking down the strengths of both guys.

"It would be a good one," said Smith ... who actually played for Fisher on the Knicks last season.

Of course, Fisher brought the feud back in the headlines Thursday -- saying he was essentially attacked by Barnes and refused to retaliate. He also said Barnes was NEVER his friend.