Anthony Joshua has accused Charles Martin of chasing quick money by making his first world title defence outside of America.
Martin puts his IBF world heavyweight title on the line for the first time against Briton Joshua (15-0, 15 KOs) at London's O2 Arena on Saturday and is reportedly being paid £6 million [$8.5m].
Joshua, the 2012 Olympic gold medallist, is convinced the American (23-0-1, 21 KOs) was persuaded to travel to the UK -- rather than fight on home soil -- by the prospect of a big pay day and because he thinks his challenger is a novice who is "easy picking".
Martin, 29, won the vacant belt in January when Ukrainian Vyacheslav Glazkov suffered a knee injury in the third round. Despite being a champion with only slightly more experience, Martin has given Joshua a slight advantage by facing the Briton at a venue where he has boxed five times before and where 20,000 fans will be cheering him on.
"Martin knows how great the UK market is and I think he's looking at it, and thinking I'm an easy picking," said Joshua.
"He said that when I met him. He said 'I'm the new world heavyweight king. I'm prepared to travel to fight the best, I'm not going to take it easy'. Or maybe he's coming either because he thinks I'm easy pickings or he wants some English money quick. Those are the two reasons I give him for coming over
"I can only rely on what I've been doing and I'm not underestimating him. He's coming prepared, he's coming dangerous. But I'm ready him -- and ready for this moment."
Joshua, who has won all 15 professional bouts by knockout, has got his world title shot ahead of schedule and admits he has not known pressure like it.
However, he seemed calm and relaxed at a public workout in front of hundreds of fans at the York Hall in east London on Monday night. Veteran American Shannon Briggs also paid a visit to check up on Joshua and Martin while trying to talk himself into a future fight.
Not since the days of Frank Bruno and Lennox Lewis has there been as much interest in the world heavyweight scene in the UK.
Joshua, 26, is attempting to become Britain's second reigning world champion along with Manchester's talkative Tyson Fury, who surprised everyone outside of his own camp when he out-pointed Wladimir Klitschko for the IBF, WBA and WBO world titles in November.
Fury (25-0, 18 KOs), 27, was harshly stripped of the IBF belt shortly after beating Klitschko for agreeing to face the Ukrainian in a rematch, which is still being negotiated.
As well as Fury and his controversial outbursts, there is also the former WBA champion David Haye (27-2, 25 KOs), who in January made a comeback after over three years in exile.
A showdown with either would be worth millions to Joshua, who has been dismissed as "useless" by Fury. Joshua feels fights against his domestic rivals can happen within a year.
"The fight I'm going into, this world title fight, is what I need," Joshua said.
"I think I need a little bit more development. The experience of it all, that mental preparation, is all stuff I need to go through. Let me handle the business in the ring and then it will be perfect for me to fight Fury.
"I think it's going to happen.
"Every era has its heavyweights -- Ali, Frazier, Foreman, then Lennox, Holyfield, Tyson and now me, Haye, Fury -- David Price is there as well -- we have to get it on. Even if it's in 12 months' time, we have to get it on.
"We can't wait any longer because we're all coming to the top of our games, we're all peaking. It's a fight [against Fury] that has to happen sooner rather than later. Even though I'm having these fights now, I know what could come in the future."
Joshua is refusing to trade insults with Fury, who last week dismissed his rival from Watford as a novice.
"He needs to be more modest, a bit more humble because when hell and thunder comes on top of him, he won't know how to handle it," said Joshua.
"He thinks he's the new Sugar Ray Robinson, but he isn't."