Referee Vic Drakulich stopped the bout at 2:20 after Zbikowski (4-0, 3 KOs), fighting at cruiserweight while NFL players are locked out,
dropped Warner (1-3) in a neutral corner with a right uppercut to the side of the face.
Warner tried to get up, but Drakulich had seen enough and ended it without administering a full 10 count.
Zbikowski, looking trim at 196 pounds, landed the first punch of the night with a straight right. Then he landed a left hook to the head followed by two shots to the body. As the fans went wild, Warner yelled at Zbikowski to keep throwing punches.
Zbikowski did, landing a right uppercut to the chin followed by more body shots that stunned Warner.
"I had to land those body shots," Zbikowski said with a smile when his night was over.
In his last fight, on March 26, Zbikowski scored a four-round unanimous decision over Caleb Grummet. But that didn't please his trainer, Hall of Famer Emanuel Steward, who went back to the basics with Zbikowski in the gym.
"The last one was a good learning experience," ZbIkowski said. "It's not the amateurs, you can't punch yourself out. The judges are looking for clean punches."
As an amateur fighting out of Chicago, Zbikowski went 75-15.
Calvin Watkins is a reporter and columnist for ESPNDallas.com.