Aberdeen Assassin Lee McAllister felt he proved the doubters wrong by defeating Danny Williams at a packed Beach Ballroom on Saturday.
The 35-year-old moved up six weight divisions to take on Williams, who defeated Mike Tyson in 2004, for the vacant WBU heavyweight belt.
Williams weighed in almost four stone heavier than McAllister for the contest at 18st 6lb but was stopped two minutes and four seconds into the 10th round.
The 45-year-old, a former two-time British and Commonwealth heavyweight champion, announced his retirement from the sport in the immediate aftermath of the fight.
McAllister, who had described the contest as the biggest fight of his career, was thrilled to come out on top but does not intend to fight at heavyweight again.
He said: “It has been awful carrying so much weight.
“The fight was hard work but I proved everyone wrong.
“I won’t be fighting again at heavyweight. My heavyweight days are done.
“I have done the Rocky story and I have made history.
“I am the first person to step up from being a lightweight world champion to become a welterweight world champion and a heavyweight world champion.
“I jumped six weights to make this fight and it paid off.”
McAllister, who suffered a nasty cut above the eye following a clash of heads in the ninth round, admitted he had struggled to prepare for the fight due to a shoulder injury.
He said: “I injured my rotator cuff and AC joint six weeks ago and I needed cortisone injections to train.
“I felt it go after four rounds.
“The shot I was working on was the left hook but, when my shoulder went, I couldn’t use that shot.
“It was a fight I wanted to tick off my bucket list and I’m pleased to come through it with the win.”
McAllister made an explosive start to the contest, flooring Williams midway through the opening round, to the delight of the crowd.
The Brixton Bomber was back on his feet by the count of five but McAllister’s speed continued to cause problems in the second before Williams was knocked to the canvas with a left hook for another count of five.
Williams, who was on the canvas twice in the fifth, upped the ante in the sixth and found a way through with a hefty shot in the seventh.
McAllister continued to be the more aggressive and landed a neat combination in the eighth before coming off second best in a nasty clash of heads in the ninth. Undeterred, McAllister floored Williams once more in the 10th round, prompting his corner to throw in the towel and end the contest.
McAllister said afterwards: “I said at the pre-fight press conference I would punch him into retirement. He laughed at me and called me a joker but it looks like that is what happened.
“I actually felt sorry for him after knocking him down so many times.
“I am glad my shoulder went as I felt bad hitting him.
“He is an absolute legend. I was just far too sharp and slick for him.”
