Tony Bellew is bracing himself for a long gruelling battle when he faces Isaac Chilemba on March 30.
Bellew hopes to land a fight against WBC champion Chad Dawson, but first he must get past Chilemba in their light-heavyweight clash at Echo Arena in Liverpool, live on Sky Sports.
The South African has suffered just one defeat and picked himself off the canvas twice in a courageous points win over Maxim Vlasov in 2011.
Bellew overcame two knockdowns in his first victory over Ovill McKenzie and believes he is facing someone with similar battling qualities.
He told the Liverpool Echo: "This is without doubt the toughest fight of my career. This guy is the most complete fighter I have faced, people have got to understand that.
"I've faced guys who are quicker than me, stronger than me and who might be better boxers than me. But I've out-hustled them.
"But this is the first time that I've faced a guy who is a good boxer, has good defence, has good speed, reasonable power and - one of the most important things - has proved he can come back after a knock down.
"I've not fought a guy who has taken a big punch and got back up. The only guy I knew that could do that in this division was me."
The Liverpudlian has 12 knockouts in his 19 wins but expects to dig deep for a victory in front of his hometown fans.
"I'm meeting someone who is very similar to me and this is the first time I've gone in with someone, thinking 'I ain't knocking this guy out'," he said.
"There is no easy way to beat this guy so I am going to have to go to the well because it is going to be a hard fight. It is going to be a nasty, hard, horrible fight but I'm prepared for that."