Nick Ball lost his WBA featherweight title after a knockout defeat to Brandon Figueroa in front of his home crowd in Liverpool on Saturday.
The fight appeared to be heading for the scorecards when 29-year-old American Figueroa produced a left-handed shot to drop the champion to the canvas in the 12th round.
Although home favourite Ball got back to his feet, Figueroa made sure the fight did not go to the scorecards when he put his opponent between the ropes and the bout was waved off by the referee.
However, chaos descended in the ring with celebrations from Figueroa's camp spilling over and prompting a melee between both camps.
Ball, undefeated in 24 previous fights, had tried to force the pace but Figueroa would not be subdued.
Figueroa made his breakthrough as the fight entered its closing three minutes when he sent Ball to the canvas with a strong left hand.
Ball regained his feet but Figueroa sensed his opportunity and completed the job soon after as he dropped Ball onto the ropes.
There had been little between the pair in many of the rounds. Ball landed some telling blows but Figueroa threw more punches.
Both had wobbles in the eighth round with Ball at one point forced onto the ropes while Figueroa went down after losing his footing.
Ball tried to step up the intensity as the end neared but Figueroa held firm and eventually prevailed.
The Wrecking Ball suffered the first defeat of his career, while Figueroa is now a three-time world champion.
World Darts Champion Luke Littler was ringside to watch his childhood friend Luke Turner in action and the 20-year-old middleweight boxer from Warrington didn't disappoint after securing his first professional stoppage win.
New champion Figueroa could now be set for a slot on the undercard of Canelo Alvarez's comeback fight in September.
After losing to Terence Crawford in a defence of his undisputed super-middleweight championship, Alvarez is expected to return to boxing in Saudi Arabia later this year.
Saudi financier Turki Alalshikh wants Figueroa to feature on the bill. "A huge congratulations to Brandon Figueroa for showing his character and travelling to the champion's backyard to capture the WBA featherweight championship with a great knockout in the final round," Alalshikh posted on social media.
"We want to see you defend your title for the first time on September 12 in Riyadh, when we stage 'Mexico vs the world' - featuring the return of Mexican superstar Saul 'Canelo' Alvarez in the main event."
Watch the Caroline Dubois vs Terri Harper bill live on Your Site on Sunday April 5.
