Thor Bjornsson beat Eddie Hall on points to settle their grudge fight after a dramatic back-and-forth encounter.
The strongmen clashed over six rounds in Dubai on Saturday night as they finally settled their long-running feud.
The pair had been at each other's throats since the World's Strongest Man competition in 2017 after which they agreed to settle their rivalry in the ring.
They were due to clash last September but Hall suffered a torn bicep in training and was forced to pull out.
Bjornsson instead fought - and stopped - arm-wrestling champion Devon Larratt in a one-sided bout.
The Icelander also took to the ring for exhibition bouts against professional boxers Steven Ward and Simon Vallily with neither bout scored nor a winner declared.
Both men had predicted a stoppage win as they took to the ring after 1am local time in front of a sparse crowd -but neither could deliver, even if Bjornsson did knock Hall down twice on his way to victory.
All three judges scored the fight 57-54 in Bjornsson's favour which did not appear to sit well with Hall.
Bjornsson was also counted in the second round when the ropes were adjudged to have held him up and when he hit the canvas later in the same session, the referee ruled the fall a slip.
"It feels amazing," said the winner. "I've been working my ass off for two years. I had such a good team around me who have supported me all the way through.
"On my behalf [the rivalry is over], understandably he seemed angry still, he lost the fight. There are a lot of feelings right now.
"If he wants a rematch I'll take one no problem. I would like to thank Eddie Hall and his team.
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"He put up a hell of a battle. I'd never been dropped in training so he really can punch hard. But today I believe boxing technique one.
"I'm really enjoying this journey and if there are other opportunities I am at least open to it."
Hall said later: "You know what, I can take things as a man. It is what it is, that's boxing. At the end of the day I've just fought the biggest man on the planet in a boxing match. I'd like to see anyone else get the balls and do that.
"It's been a hell of a journey; I've enjoyed it and hopefully there's a rematch and we can do business again.
"I want to wish everyone out there.. that you're staying safe, sating positive and you keep moving forward in life. The most important thing is family; this gorgeous baby [Hall's wife] is my rock and no matter what happens I get to go home to her and the kids."
