Tomoki Kameda came up short in his bid to wrest the WBA bantamweight title away from England's Jamie McDonnell on Saturday, losing by unanimous decision.
Kameda floored McDonnell in the third round at State Farm Arena and felt he had been hard done by as three scores of 114-113 gave McDonnell victory and the Japanese his first career defeat.
"I don't think I lost so I don't feel disappointment," said the 23-year-old Kameda, whose team hinted it will ask the World Boxing Association to hold a rematch.
"I believe I won. There is not much you can do (about the judges' decisions.)
"A Japanese and English boxer were fighting in America and the fans (booing the decision) knew (I was the winner)."
Kameda dropped to 31-1 (19 knockouts) while McDonnell improved to 26 wins (12 KOs) against two losses and a draw.
Kameda vacated his WBO bantamweight world title last month, with the move coming days after the World Boxing Organization announced it would not authorize a proposed unification bout between Kameda and McDonnell.
The organization said it did not recognize McDonnell as the WBA champion, due to Juan Carlos Payano's status as "super" champion.
Kameda won a split decision against interim champion Alejandro Hernandez of Mexico to successfully defend his WBO title for the third time in Chicago in November 2014.