Deontay Wilder has criticised Anthony Joshua for a lack of confidence after the Briton suggested he may not be ready for a heavyweight unification bout until 2019 or 2020.
Wilder is the WBC champion in the top weight class and is poised to defend that belt against Bermane Stiverne next month after his previous scheduled fight with Luis Ortiz was cancelled due to the Cuban failing a drugs test.
IBF, WBA and IBO champion Joshua takes on Kubrat Pulev on October 28 but has hinted a fight with Wilder may be some way off.
Responding to those remarks, Wilder - who is 38-0 with all but one of those wins by knockout - said: "What other heavyweight does what I do? What other heavyweight has the power like me, I don't have to punch in bunches, one punch goodnight.
"I am the most feared, the baddest, the hard-hitting heavyweight and please tell your favourite fighter to come and see me.
"My doors are open, my jungle is free, please travel down this path with me and see who comes out on top and I promise you this boy right here - this black American from Alabama - will come out on top each and every time, I'll put my money on that.
"In this boxing thing you have to have competition... you have to sound like you're the best, you can never sound like you need more time for another champion to prepare to put yourself in a better position AJ! That doesn't sound too confident."
Joshua is seen as the king of the heavyweight division following his thrilling 11th-round stoppage of Wladimir Klitschko in April.
But Wilder feels he deserves the same respect, adding: "Don't be fooled, do your research when you come to criticise me.
"The thing about fighters from other countries, their people are behind them, they support them no matter what, a lot of you won't want to hear that but that's okay, do your research.
"Make sure you get your information right about me, make sure you do your research so when you write your blogs, when you do your videos, when you go and tell the stories about Deontay Wilder, you get it correct."