UK light heavyweight Buatsi earned a win yet disappointing start to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a competitive 10-round contest at the Manchester venue.
But the challenger landed significant shots, delivering effective clean blows in a match where the approaches didn't complement each other, with excessive holding spoiling the fight.
The officials judged it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my best performance but what do champions do? They succeed," the victor stated in the arena as he was faced boos from the crowd.
The Londoner bounced back after his first professional defeat - an memorable fight with his previous opponent in February - to earn a 20th pro success.
Some ringside observers felt Parker, thirty-one, deserved the win but the British boxer suffered the second defeat of his 28-bout career.
Buatsi Secures Triumph in Dull Encounter
Buatsi's progress has plateaued in recent years through contract problems and extended periods of lack of fights.
Earlier forecast as the rising talent of UK boxing, he now is positioned trying to achieve expectations - perhaps in what seems like a last chance - under recent support.
He started carefully, with neither fighter willing to be aggressive in a calculated opening few rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was competing in only his second fight at light heavyweight.
By the fight's midpoint, the underdog had stayed in contention, creating difficulties for the favorite, who utilized a solid defense to barely take the more effective stanzas.
The audience's tolerance decreased during regular grabbing, with Parker going down various instances during grappling.
The underdog ended stronger, but multiple periods were hard to judge. However, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, giving Buatsi just one round.
Buatsi moves on, but with the caliber of power puncher David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Hatton Homage Fuels Manchester Derby Fight
In the secondary fight, Arthur beat Rea by close verdict in a excellent Manchester vs Manchester contest to secure the continental belt.
The arena grew hushed for a extremely emotional homage before the fight as ten bells rang in honor of Manchester's own Hatton, who passed away 46 years old in last month.
It was the first major televised match card in the location since the passing of Hatton. As the last bell ended, the quiet became a chant of "there's just one Ricky Hatton".
The action within the ring matched the feeling. Arthur was knocked down by a significant blow directly to the jaw in the initial stage, rising shakily to his footing on the eight count.
But the Manchester United-red equipment of the fighter soon came forward again. On the opposite side, Rea - in rival City blue - was injured early, noticeable damage developing under his orbital area as the duo exchanged punishing blows.
Rea, twenty-seven, connected with strong blows but Arthur, 34, responded in kind with effective uppercuts as the action seldom decreased over 12 rounds.
Arthur narrowly won the decision with judges scorecards of draw, 115-113 and 115-112, but each competitor were determined and full of heart, all the qualities their idol Hatton stood for.
