Lyndon Arthur survived a scare against late replacement Boris Crighton before sealing a unanimous points victory.
Arthur was due to fight Braian Nahuel Suarez for the vacant IBO light heavyweight championship before the Argentinean failed a pre-fight medical.
Scot Crighton, called up at a day’s notice, performed admirably in his place but Manchester’s Arthur finished strongly in the final two rounds.
He won 98-92 96-93 99-91 on the judges’ scorecard in Bolton.
Arthur, one of a number of highly-rated British light-heavyweights, now holds a 22-1 record and will fight for the world title next.
“He was completely different style to what I was training for,” the 31-year-old said. “It was a good 10 rounds before a bigger fight.”
Arthur’s most high-profile win was a split-decision victory over another Briton, Anthony Yarde, in December 2020, but he was spectacularly knocked out in the fourth round of their rematch a year later.
Crighton, who previously sparred with Arthur, is a two-time Great Britain amateur champion but usually fights at super-middleweight.
He landed a right hand in the third round but after a cagey period Arthur came out strongly in the ninth before flooring his opponent with a strong right hand seconds before the final bell.