UK light heavyweight Buatsi earned a win yet unimpressive beginning to life under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a tight 10-round fight at the Co-op Live Arena.
But Parker found success, landing some telling clean blows in a fight where the techniques didn't complement each other, with frequent clinching disrupting the contest.
Two judges had it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my greatest display but how do champions respond? They prevail," the victor commented in the ringside as he was met by negative reactions from the crowd.
The Londoner bounced back after his first professional defeat - an memorable fight with Callum Smith in February - to secure a 20th career victory.
Some ringside observers felt the challenger, 31, should have been awarded the victory but the British boxer suffered the second defeat of his 28-bout professional journey.
Buatsi Claims Win in Uneventful Affair
Buatsi's progress has slowed in recent years through promotional disputes and considerable time of lack of fights.
Earlier forecast as the future of UK boxing, he now finds himself trying to achieve expectations - maybe in what feels like a final roll of the dice - under recent support.
He opened tentatively, with both competitors ready to be aggressive in a calculated early stages.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand during the bout, was participating in his second fight at light heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for the favorite, who operated with a tight guard to narrowly win the more effective rounds.
The audience's tolerance diminished because of constant clinching, with Parker slipping to the canvas several times during grappling.
Parker ended stronger, but many rounds were challenging to assess. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
The victor moves on, but with the likes of hard hitter David Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - judging by this showing - still looks steep.
Hatton Memorial Fuels Manchester Derby Battle
In the secondary fight, Arthur beat Rea by close verdict in a excellent all-Manchester contest to capture the European light-heavyweight title.
The venue grew hushed for a deeply poignant tribute before the fight as a bell ceremony rang in memory of the city's native Hatton, who succumbed aged 46 in September.
It was the premier televised match card in the city since the passing of Hatton. As the final chime disappeared, the stillness transitioned to a roar of "there's only one Hatton".
The competition during the bout reflected the feeling. The eventual winner was floored by a powerful punch flush on the jaw in the second round, standing uncertainly to his feet on the referee's count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. Across the ring, the opponent - in opposing blue - was injured quickly, significant bruising developing under his face as the fighters exchanged hard punches.
Rea, 27, connected with strong blows but the champion, 34, responded in kind with powerful upward punches as the action hardly diminished over the full distance.
The victor barely secured the verdict with scoring tallies of 114-114, close margin and clearer margin, but the two athletes were determined and full of heart, everything their idol the legend embodied.
