Anthony Joshua is under no illusions over the threat posed by late replacement Carlos Takam ahead of his world heavyweight title defence in Cardiff on October 28.
Joshua has revealed he was ambushed by Takam in a hotel lobby shortly after the first defence of his IBF crown against Dominic Breazeale last year - and knows the Frenchman will be eager to grasp his "golden ticket".
With 70,000 tickets already sold at the Principality Stadium, Joshua's promoter Eddie Hearn was forced to finalise a late deal with Takam - who was already on stand-by - when mandatory challenger Kubrat Pulev pulled out on Monday with an upper-arm injury.
Joshua, the IBF, IBO and WBA champion, said: "After I fought at the O2 (against Breazeale), Takam waited at my hotel in reception and said to me, 'I want to fight you!'.
"He came to the fight, then waited for me in reception. I knew who he was. He's a big unit, 22 stone, and I think he will be harder to knock out because he's incredibly durable."
Takam brings with him a record of 35 wins from his 39 bouts, with only one stoppage loss against Alexander Povetkin, and a points defeat to WBO king Joseph Parker, the recent low-key conqueror of Hughie Fury, in New Zealand last year.
Although like Pulev he will start as a significant underdog, he is far from the worst late replacement Hearn could have mustered, and brings the added benefit of enabling Joshua to get his mandatory title defence out of the way before targeting bigger prizes next year.
Joshua said he did not find out about Pulev's withdrawal until it began to be reported last night, but said it would do little to deflect his preparations for his fourth consecutive title defence.
He added: "Takam has fought some good people, but maybe because he's not so active on social media, the general public might not know much about him. He's a credible opponent and we can't take our eye off the prize.
"He is not going to come in and lie down in the first round. I think that's the mindset of anyone who fights me, because he is in hostile territory with a lot of people who are not there to support him so he will think, 'what have I got to lose?
"This is his golden ticket to shock the world."