UK light heavyweight Buatsi earned a win yet underwhelming debut to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a split decision in a close ten-round bout at the boxing arena.
But the challenger landed significant shots, delivering effective single shots in a match where the styles never quite clicked, with excessive holding disrupting the action.
Two judges scored it 96-94 to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest display but what defines champions? They win," the victor stated in the ringside as he was met by disapproval from the audience.
The British fighter got back to winning after his maiden career setback - an epic battle with Callum Smith in February - to secure a 20th pro success.
Several boxing experts felt the challenger, thirty-one, deserved the decision but the Derbyshire fighter experienced the second defeat of his 28-fight career.
Buatsi Earns Victory in Uneventful Match
His career development has plateaued in recent years through contract problems and considerable time of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to realize his potential - possibly in what seems like a ultimate opportunity - under new promotional backing.
He started carefully, with neither fighter ready to overcommit in a tentative initial rounds.
Parker, whose only previous defeat came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was participating in his second bout at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to barely take the better rounds.
The audience's tolerance diminished during frequent holding, with Parker going down various instances during close exchanges.
Parker finished the stronger, but many rounds were difficult to score. Although, former world champion the boxing analyst - working with Dazn - had it strongly leaning for Parker, giving Buatsi just a single round.
The victor progresses, but with the likes of hard hitter David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still seems difficult.
Ricky Hatton Homage Inspires All-Manchester Contest
In the co-main event, Arthur defeated Bradley Rea by divided decision in a terrific local rivalry contest to capture the European light heavyweight championship.
The arena fell silent for a profoundly moving tribute prior to the bout as a bell ceremony rang in memory of local hero Hatton, who passed away at age 46 in September.
It was the initial significant broadcast match card in the urban center since the passing of Hatton. As the concluding sound disappeared, the stillness gave way to a roar of "there's just one Ricky Hatton".
The action within the ring equaled the sentiment. Arthur was sent to the canvas by a significant blow squarely on the face in the initial stage, rising shakily to his footing on the count of eight.
But the traditional red attire of the fighter soon came forward again. Across the ring, Rea - in competitive blue - was injured early, significant bruising appearing under his eye as the pair landed powerful shots.
Rea, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity hardly diminished over twelve rounds.
Arthur edged the verdict with judges scorecards of 114-114, close margin and wider gap, but each competitor were persistent and full of heart, everything their idol the legend stood for.
