Anthony Joshua and Deontay Wilder must meet in a unification fight next with "no excuses", according to promoter Eddie Hearn.
WBC champion Wilder knocked out Dominic Breazeale with a mighty right after just 137 seconds at Barclays Center on Saturday.
The 33-year-old Alabama native failed to agree terms for a bout with IBF, WBA and WBO champion Joshua last year and instead took on former champion Tyson Fury in a thrilling encounter that ended in a draw.
With Wilder having seen off Breazeale and Joshua set to defend his belts against Andy Ruiz Jr in his United States debut on June 1, Hearn believes the time has come for the two heavyweight kings to meet in the ring.
"That was an impressive win for Deontay - he's exciting to watch," Hearn told Sky Sports.
"He has taken care of business, now AJ needs to do the same against Ruiz Jr at Madison Square Garden on June 1.
"The fight with AJ and Wilder is the biggest fight in the sport , all being well in two weeks' time, it must happen next - no excuses, this is the fight that will change the sport globally.
"It's a legacy fight and AJ wants it so bad. Two big, fast, dangerous and fearless world heavyweight world champions that can turn the lights out in a blink of the eye - it's a must.
"First things first, taking care of business on his American debut on June 1 and sending a message straight back."
The hurt business pic.twitter.com/t7WB0KfS2t
— Anthony Joshua (@anthonyfjoshua) May 14, 2019
Wilder promised a meeting with Joshua will occur following his victory over Breazeale but urged patience amid suggestions rematches with Fury or Luis Ortiz could also be in the offing.
"The big fight will happen, I promise you that, with patience, come time, and I just want you guys to have patience and give us a little time to make this thing happen so we all benefit from it, not only just you fans," he said.
"We risk our lives in here so we want to make sure we get the best and the most money that's possible.
"We're risking our lives - the head is not meant to be hit in the first place. So let us get our time to iron out all the differences and you guys will know when that happens."
