Gennady Golovkin has a serious plan for his upcoming middleweight title fight with Kell Brook, who he has labelled as the biggest challenge of his career.
Golovkin will aim to take his professional record to 36-0 when he defends his WBC, IBF and IBO middleweight titles on Saturday at London's O2 Arena against IBF welterweight champion Brook, who goes into his 37th career bout also still yet to taste defeat.
The Kazakh goes into the fight as heavy favourite with Brook having jumped up two weight classes, but Golovkin is wary of threat posed by his British opponent.
Golovkin told Sky Sports: "He [Brook] came in a month before the fight at 176lbs and then 167lbs. My weight has been 165 or 163 but he's huge. He looks good. He looks strong and big. It's interesting. It's very serious and it's a huge fight.
"My first question to my coach was about [Brook having] different speed but he said no - just different size, different power and different timing. I thought 'Wow'. It's interesting.
"He's my biggest fight and my biggest challenge. It's my biggest step. UK fans are huge and crazy. I like the atmosphere.
"I feel great. I feel it's time to fight. I have two or three days and then I'll be feeling ready, 100 per cent. I have to thank my coach, Abel Sanchez, who brought a new strategy for this. It feels great. I feel different and I feel good.
"I have a different plan and a more serious plan. Kell is a great fighter and I respect him. He's an undefeated champion from the UK with a great record. I understand it's not an easy fight for us so I'm more serious and more focused."