Nathan Cleverly has issued a warning to Robin Krasniqi ahead of the pair's WBO light-heavyweight title match this weekend.
The Welsh scrapper told his opponent that heavyweights including Dereck Chisora and Tyson Fury have failed to put him down in sparring sessions.
"It's nice to be taken out of your comfort zone and face guys who are heavier than you and who can push you around," ESPN quotes him as saying. "It's good to not have things your own way and these guys test your chin and how you respond.
"Sometimes I stand and trade with the heavyweights. It's macho, you could say it's a bit silly, but that's my mentality. I love to go to war sometimes.
"I have a granite chin and have never been put down, but the heavyweights really test my chin. It's a challenge but it gives me confidence when I take their shots."
Cleverly and Krasniqi clash at Wembley Arena on Saturday, with the defending champion likely to go on to face Bernard Hopkins should he defeat his opponent.