Deontay Wilder has been pursuing a fight with Anthony Joshua for some time.
But, after the American's brutal first round knockout of Bermane Stiverne last weekend, Wilder has upped his efforts to fight the Englishman.
Immediately after his victory Wilder called out Joshua, saying: "I know I am the best. Are you up for the test?
"I've been waiting on that fight for a long time now. I declare war upon you. Do you accept my challenge?"
And the American then followed up that message on Twitter, writing: "The world wants Joshua, the world wants Wilder, I want Joshua. Joshua, come and see me baby. No more dodging, no more excuses. Make the date, don't wait. Let's see who is the best."
WILDER'S HOPES OF FIGHTING JOSHUA MAY HAVE STALLED AGAIN
However, Wilder may have to wait even longer for his dream fight with Anthony Joshua, as it seems the Englishman is pursuing a fight with another challenger.
Joshua has no shortage of options, with Tyson Fury, Joseph Parker and Wilder, amongst others, all potential bouts.
But it looks as if Joshua's next fight may be with Parker, after it was revealed that his promoter, David Higgins, has exchanged emails with Joshua's promoter, Eddie Hearn.
Higgins told reporters in Auckland, as per Sky Sports: "Eddie Hearn and I have exchanged emails.
"My message was Joe would fight Joshua next and Hearn's message was that Joshua would fight Parker next.
"It's now a question of the deal and money."
WILDER BLAMES EDDIE HEARN FOR THE FIGHT STALLING
And Wilder has launched a stunning accusation against Eddie Hearn, claiming that he is the main factor which is preventing his fight with Joshua.
Wilder told BBC Radio 5 Live, as per the Daily Express: "I think Eddie is ducking me more so than Joshua.
"If Joshua's a strong champion, a true champion, you guys in England should smoke him out, make him fight. You should see if he's the best.
"My heart says I'm the best, if I'm not I want someone to show me."
WILDER ALSO CLAIMS HE WILL COME TO ENGLAND TO FIGHT
And Wilder has shown he will do almost anything to get his fight with Joshua, by claiming he will have no qualms coming to England for the bout.
He said: "Packing out stadiums looks good but the money and Mecca of boxing is in America.
"But if you want to stay at home like a little girl, this king has no problem travelling to knock out the champion."