Eddie Hearn admits Anthony Joshua needs to be wary of history repeating itself when he faces Kubrat Pulev next month.
A potential unification bout with Tyson Fury looms large for 'AJ', just as it did when he was knocked down by Andy Ruiz with a fight against Deontay Wilder expected to follow.
Hearn says looking past the Bulgarian, whose professional record stands at 28-1, is simply not an option for Joshua on 12 December.
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"I think we've got to be careful, because we made the mistake (of looking too far ahead) in the Ruiz fight," said the Matchroom supremo.
"AJ's learned from that. He didn't not train hard because of it, but all anyone was talking about was the Wilder undisputed fight.
"I remember being in New York and we went to ESPN to promote the Ruiz fight and they didn't ask one question on Ruiz - every one was on Wilder.
"AJ isn't looking past Pulev and nor are the team, we remember that night and it still hurts to this day.
"The end goal is to become undisputed heavyweight world champion, but unless he beats Pulev that dream is finished.
"The way he's training, the way he's preparing I don't see him looking past Pulev and I think he's going to do a devastating job on him."
Joshua will defend four heavyweight title belts - WBA, IBF, WBO and IBO - against Pulev whose only defeat came against Wladimir Klitschko in 2014.
The fight, staged at the O2 Arena, is set to go ahead without fans and Hearn thinks that could be one of the biggest pitfalls for his charge.
Joshua is a stadium fighter used to boxing in front of crowds of up to 90,000 and his promoter says he's concerned about the uncertainty brought by an empty arena.
"The main concern is the new environment we're in," said Hearn.
"It's a fascinating environment to be in in terms of the atmosphere and the intensity, the silence.
"AJ is a guy that has boxed his whole career in front of sold-out arenas - now it's about 80 people and you can hear a pin drop.
"There's the argument that maybe AJ won't be able to get himself up for it as quickly, or the argument you can be almost more at peace with what you're doing, listen to your trainer and carry out the strategy you've worked on for the last 12 weeks.
"I don't know what the answer is but it does concern me because you've seen flat performances, some great performances when we're continued boxing without crowds. I don't know who it's going to favour, but I would much rather it being in the normal surroundings."
Hearn took time out of his busy schedule to back a new volunteering initiative from The National Lottery and ITV.
Miss Out To Help Out encourages the public to use the time they spend watching their favourite TV show helping out in their community.
Hearn himself spent an hour virtually volunteering and talking to 12 members of charity Sporting Memories - one of the thousands of community groups supported by some of the £30m raised by Lottery players for good causes weekly.
"Volunteering with Sporting Memories was a really rewarding experience," said Eddie.
"To witness first-hand the impact, you can have on the wellbeing of an individual just by giving a small amount of your time to help out was so nice to see.
"I'd like to encourage everyone who has a bit of time to spare to go to MissOutTohelpOut.com to explore how they can support their local community."
- Miss Out to Help Out is encouraging the public to miss out on their favourite TV shows and instead use that time to 'help out' in their community - a new initiative from The National Lottery and ITV.
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