It is boxing brain over brawn for Vitali Klitschko, who believes brother Wladimir's smarts inside the ring will upstage the muscular physique of Anthony Joshua.
Joshua, 27, will defend his IBF heavyweight title against former linear champion Wladimir Klitschko in front of 90,000 spectators at Wembley on April 29.
Olympic gold medallist and Englishman Joshua (18-0) will put his title on the line against 40-year-old Ukrainian Klitschko (64-4), whose reign as champion came to a surprise end against Tyron Fury in November 2015.
Many believe Joshua's youth and physique give him the edge but Vitali - a former champion himself - is confident Wladimir's experience will help him emerge triumphant.
"Many people think muscles are important in boxing," Vitali Klitschko told Sky Sports. "It's not. Everything is here, in the head.
"He's much more focused right now than many years ago. I hope he knows from his focus, from his concentration, that this fight depends a lot and that's why everyone expects a great fight.
"Yes of course we expect a good performance from Wladimir and yes of course Wladimir has to be the winner on April 29.
"Wladimir has already big experience of fighting in an arena. He's used to fighting in a stadium, pressure from the crowd, from attention.
"It will be something new for Joshua and nothing special for Wladimir."