UK light-heavyweight Buatsi made a winning yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a majority decision in a competitive 10-round bout at the Co-op Live Arena.
But Parker had his moments, landing some telling individual punches in a contest where the approaches failed to mesh, with constant grabbing spoiling the action.
The officials judged it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest performance but how do champions respond? They prevail," Buatsi stated in the ringside as he was greeted with disapproval from the audience.
The Londoner got back to winning after his first professional defeat - an memorable fight with Callum Smith in last winter - to secure a 20th pro success.
Several boxing experts thought Parker, 31, deserved the victory but the British boxer suffered the second defeat of his 28-bout career.
The Champion Secures Triumph in Dull Match
Buatsi's progress has slowed in the past few years through promotional disputes and considerable time of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to achieve expectations - maybe in what seems like a last chance - under fresh management.
He began cautiously, with both competitors prepared to be aggressive in a tentative initial rounds.
Parker, whose only previous defeat came at the lower weight class against John Ryder in 2022 after damaging his hand in the contest, was making just his second fight at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for Buatsi, who utilized a protective stance to barely take the better periods.
The audience's tolerance diminished because of regular grabbing, with Parker going down various instances during clinches.
The underdog finished the stronger, but several stanzas were difficult to score. Although, ex-champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
The victor moves on, but with the likes of heavy hitter David Benavidez, and Russian star Dmitry Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Hatton Tribute Fuels All-Manchester Contest
In the supporting bout, Arthur beat Bradley Rea by divided decision in a outstanding all-Manchester battle to win the European light-heavyweight title.
The arena fell silent for a deeply poignant tribute prior to the bout as ten bells sounded in memory of the city's native Ricky Hatton, who died 46 years old in last month.
It was the initial significant broadcast match card in the urban center since Hatton's death. As the last bell disappeared, the quiet became a roar of "there's only one Hatton".
The fighting during the bout equaled the emotion. The eventual winner was floored by a powerful punch squarely on the face in the second round, rising shakily to his position on the count of eight.
But the traditional red shorts of the fighter soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was damaged quickly, heavy swelling forming under his orbital area as the pair exchanged punishing blows.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with stinging uppercuts as the intensity rarely dropped over 12 rounds.
Arthur barely secured the verdict with judges scorecards of draw, close margin and clearer margin, but each competitor were persistent and courageous, all the qualities their inspiration the legend represented.
