Wladimir Klitschko says he is "embarrassed for the sport of boxing to have a heavyweight champion like Tyson Fury".
Fury defeated Klitschko to clinch the IBF, WBA, WBO and IBO titles in Dusseldorf in November. The Brit has since been stripped of the IBF belt, which now belongs to compatriot Anthony Joshua.
The pair will meet for a rematch at Manchester Arena on July 9.
And Klitschko, who criticised his opponent's often controversial views, says he is intent on avenging that defeat.
"I am embarrassed for the sport of boxing to have a heavyweight champion like Fury," he told talkSPORT.
"I do not accept anything that comes out of his mouth, which is disgraceful to a lot of people. The statement he makes are not what a heavyweight world champion should say.
"There are so many Klitschko fans even in Manchester saying: 'please, do it for us, knock him out!'
"I am here in Manchester, in his hometown, and I am looking forward to getting my revenge.
"I made a mistake in the last fight and for the first time in 11-and-a-half years I lost. In the past with the three losses I had I have always come back stronger - and I will come back again."