British light-heavyweight Buatsi earned a win yet underwhelming start to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output likely gained him a majority decision in a competitive 10-round fight at the boxing arena.
But the challenger landed significant shots, delivering effective individual punches in a match where the styles failed to mesh, with excessive holding marring the fight.
Two judges had it 96-94 to Buatsi, with the third a 95-95 draw.
"It wasn't my greatest display but what defines champions? They succeed," the victor said in the arena as he was met by disapproval from the crowd.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts believed the challenger, 31, should have been awarded the decision but the contender suffered the second loss of his 28-match professional journey.
Buatsi Claims Win in Dull Match
His career development has slowed in the past few years through contract problems and extended periods of inactivity.
Once tipped as the future of British boxing, he now stands trying to fulfil that early promise - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with the two boxers ready to be aggressive in a cagey early stages.
Parker, whose single earlier setback came at super middleweight against John Ryder in 2022 after damaging his hand mid-fight, was competing in only his second bout at the higher weight class.
By the middle rounds, the underdog had made it competitive, creating difficulties for Buatsi, who worked behind a solid defense to narrowly win the cleaner rounds.
The audience's tolerance decreased during frequent holding, with the challenger going down various instances during grappling.
The underdog finished the stronger, but many rounds were hard to judge. Although, former world champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of power puncher David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Homage Fuels Local Rivalry Battle
In the co-main event, Arthur beat Bradley Rea by split-decision in a outstanding all-Manchester fight to capture the European light heavyweight title.
The stadium grew hushed for a extremely emotional tribute prior to the bout as a bell ceremony sounded in honor of the city's native Hatton, who passed away at age 46 in September.
It was the first major televised boxing event in the city since the passing of Hatton. As the concluding sound ended, the silence gave way to a roar of "there's just one Ricky Hatton".
The fighting during the bout reflected the sentiment. Arthur was sent to the canvas by a left hook squarely on the jaw in the initial stage, rising shakily to his footing on the referee's count.
But the traditional red shorts of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was marked up quickly, heavy swelling forming under his orbital area as the pair exchanged punishing blows.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with effective uppercuts as the action seldom decreased over twelve rounds.
Arthur narrowly won the decision with judges scorecards of 114-114, close margin and 115-112, but each competitor were relentless and full of heart, everything their inspiration the legend stood for.
