Amir Khan has been warned not to risk his unbeaten record by taking unneccessary risks against former world champion Gairy St Clair next month.
One-time IBF super-featherweight title holder St Clair, 32, has never been stopped in his 46-fight career.
The Guyana-born Australian challenges Khan for his Commonwealth lightweight crown in London on 2 February.
Khan's promoter Frank Warren said: "Amir's a macho character and takes risks, but I'd prefer him not to."
Warren is concerned that "Superman" St Clair, who has stepped in to replace the injured Martin Kristjansen, could be the man to exploit any lapse in concentration from the 21-year-old Bolton star.
While he has campaigned most of his career at the super-featherweight limit, St Clair has moved up for big fights against the likes of the late Diego Corrales and former WBA light-welterweight king Vivian Harris, both of whom he took the distance.
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Warren added: "The crowds come to watch Amir because he takes risks just like Nigel Benn before him.
"But all good fighters have been on the floor and Amir's got to learn from that. Gairy is the type of fighter who will really make him think."
St Clair insisted: "Many have tried to stop the 'Superman' but I'm hard as a rock and I'll be there from the first minute to the last.
"Amir is a good young fighter but I've got a lot of experience. I've been down and out a couple of times but I've always fought back.
"I've always fought bigger guys than me but I've always had a tremendous chin.
"I take fights at whatever weight. I've sometimes struggled but this is the time for me to get big fights."
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