Anthony Joshua has warned heavyweight rivals Deontay Wilder and Tyson Fury that he is still improving as a fighter and they would be well advised to take him on sooner rather than later.
Joshua, the IBF, WBA and WBO champion, has repeatedly failed to secure a fight with the other two leading names in the division, with high-profile negotiations with Wilder, in particular, failing time and again.
The Briton, 22-0 with 21 knockouts, will next face Andy Ruiz Jr. on June 1 at Madison Square Garden, but he believes Wilder and Fury are taking a risk by delaying any clash with him.
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Joshua claims he has been steadily improving since beating Wladimir Klitschko in April 2017 and expects his hard work to pay off against his next opponent.
"After the Klitschko fight two years ago, I was in a really tough fight that could have gone either way," he told BBC 5 live's boxing podcast.
"So, for those two years, with my team, [it has been] 'How do we now train smart to become smarter in the ring?' Less quantity, more quality. It's about the quality work now.
I am the I am pic.twitter.com/16PS1Siabp
— Anthony Joshua (@anthonyfjoshua) May 1, 2019
"It didn't happen overnight. We're still developing now, I'm a product of what I'm taught. It took me two years to implement [different techniques] and this is the first training camp where we're actually using it now.
"If you look at my fight against [Alexander] Povetkin, I was ill, tired, had a flu, had a headache. Against [Carlos] Takam, I was overweight. I was going through so many changes, wondering how come I wasn't getting it perfect.
"Those last two years, we've worked tirelessly. We've traveled all around the United States, meeting Navy SEALs experts, team bonding experts, using recovery equipment that Klitschko was using years ago, lights that NASA use.
"There are all these things trying to improve our training camp and move to the future instead of staying stuck in the old ways of boxing. It's going to be interesting because now is the first time I'm going to be able to express these things.
"The longer Wilder and Fury leave it, the tougher I think the fight will become for them. I'm not the fighter of two years ago. They've been doing it 10, 11 years, I've been doing it five, six years.
"Give me another year or two, I think I'll develop that little bit more. I only want to improve and test myself."