Kid Galahad defeated Jazza Dickens with a stoppage at the end of the 11th round of an all-British contest to claim the vacant IBF world featherweight title.
The 31-year-old dominated the bout at the Matchroom Fight Camp in Essex on Saturday.
The fight was stopped with blood pouring from above the left eye of Dickens after a cut he suffered in the first round.
It is Galahad's first world title win in his 29th bout as a professional.
Former champion Josh Warrington had given up the title in January after holding the belt since May 2018.
Dickens suffered a cut to his left eyelid early in the bout and later appeared to have suffered a broken nose.
Galahad's only previous world title fight ended in a split-decision points defeat against Warrington in 2019.
"It's unbelievable," he said. "After 19 years' hard work, I've finally got the title round my waist. It's been a long time.
"I didn't want to leave it to the referees or judges. Now I want to win a couple more titles and unify the division.
"If I fight Warrington, he's not going 12 rounds."
Speaking on BBC Radio 5 Live, British heavyweight Dillian Whyte said: "Dickens is a brave man but I think they made him take too much punishment. His nose went, his eyes went, but his corner should have protected him better tonight."
Pundit Steve Bunce added: "It's been a terrific fight, so much better than we expected and competitive - even though we all had Galahad in front.
"That is one of the worst cuts I've ever seen. A cut like that could end a career."
The pair had previously met in 2013 when Galahad beat Dickens with a 10th-round stoppage when they fought for the British title at super-bantamweight.