Anthony Joshua wants a rematch with Dillian Whyte and immediately enquired about fighting him on Oct. 28 when Kubrat Pulev pulled out.
Joshua and Whyte have history, with Whyte defeating his English rival when both were amateurs in 2009 before Joshua got revenge -- after overcoming a brief moment of concern -- with a spectacular seventh round knockout in December 2015.
Since then, Joshua (19-0, 19 KOs) has won the IBF and WBA world heavyweight titles and makes a fourth defence against Cameroon's Paris-based Carlos Takam (35-3-1, 27 KOs), who stepped in at 12 days notice after Bulgarian Pulev injured a shoulder in training.
But Joshua, 28, who won the 2012 Olympic super-heavyweight gold as an amateur, first asked promoter Eddie Hearn if a rematch with Whyte (21-1, 16 KOs) could instead be made and considers beating his domestic rival his biggest professional career highlight, along with April's thrilling 11th round win over former long-reigning world champion Wladimir Klitschko.
"Dillian was the first person I asked to fight in Cardiff," said Joshua. "Because the two people who brought the best out of me entertainment-wise were Dillian and Klitschko.
"Klitschko, I was buzzing for a rematch because of the type of fight it was, it was great. Dillian, the same reason, it was just a buzz, everyone had a good time.
"Let's look back at certain careers -- if you can pick memorable nights Dillian would be one and Klitschko would be one. Out of my career there should be four or five memorable nights and we've already ticked off two."
Whyte, 29, is also in action on Saturday and fights Finland's Robert Helenius on the undercard in Cardiff. Victory for Whyte, who moved to London from Jamaica aged 12, will move him closer to a first world title shot and Hearn hopes it will be against WBC champion Deontay Wilder (38-0, 37 KOs), of Alabama, in London Feb. 3.
"Dillian has a good fight against Helenius, but if Dillian wins I'd like to see him fight Wilder," said Hearn. "AJ will have a fight in March or something like that, then we fight the winner of Wilder-Whyte in the summer for the unification."
Wilder makes a sixth title defence against Haiti's Las Vegas-based Bermane Stiverne (25-2-1, 21 KOs) in a rematch on Nov. 4 after Cuban Luis Ortiz -- his original opponent -- failed a drugs test last month.
The American has been calling on Joshua, rather than Whyte, to fight him in the States and Hearn insists Joshua deserves the bigger share of the purse.
"The deal in Wilder's head is a 50-50 split between Deontay Wilder and Anthony Joshua, but over my dead body is that ever happening," said Hearn.
"He needs to fight someone real. That's why I want him to fight Dillian Whyte, Feb. 3 at the O2 in London."
To stay on course for either Wilder or Whyte, Joshua needs to take care of Takam, 36, in a fight worth around £15 million ($19.7 million) to him.
Joshua, who lives in north London when he's not training in Sheffield, is a big favourite to overcome Takam, who lost to New Zealand's Joseph Parker -- now the WBO titleholder -- last year and before that by knockout to Russian Alexander Povetkin in 2014.
But Takam has the opportunity, as well as a big payday, after Pulev pulled out injured but Joshua insists he has gone through with fights injured.
"I had glandular fever against Dominic Breazeale in June 2016, my shoulder in this camp," said Joshua. "Fighters go through a lot. Two weeks before the Klitschko fight I went for a Thai massage and she stretched me. She pulled my arm down my leg and it cramped my back.
"I swear, I was walking doubled over. Two weeks before. But we crack on. I fought Michael Sprott with a fractured back, just crack on.
"You build up so much to this one moment and because of a niggle you're going to let it go. I don't think, touch wood, unless it was serious, serious, I don't think I'd stop."