UK light heavyweight Buatsi made a winning yet underwhelming beginning to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a competitive 10-round fight at the Manchester venue.
But Parker found success, landing some telling single shots in a match where the techniques didn't complement each other, with constant grabbing disrupting the action.
The officials had it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest showing but what defines champions? They prevail," the victor said in the ringside as he was greeted with boos from the crowd.
The Londoner got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Some ringside observers thought Parker, 31, deserved the decision but the contender suffered the second setback of his 28-bout professional journey.
Buatsi Secures Victory in Slow Affair
The fighter's advancement has slowed in recent times through contract problems and long spells of inactivity.
Previously predicted as the rising talent of UK boxing, he now finds himself trying to achieve expectations - maybe in what feels like a last chance - under recent support.
He started carefully, with neither fighter willing to overcommit in a cagey initial rounds.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in 2022 after damaging his hand in the contest, was competing in only his second fight at the higher weight class.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who worked behind a solid defense to narrowly win the more effective stanzas.
The audience's tolerance wore thin amid regular grabbing, with the challenger slipping to the canvas several times during grappling.
The underdog ended stronger, but many rounds were difficult to score. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it significantly in favor for Parker, giving Buatsi just one round.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Hatton Homage Motivates Local Rivalry Fight
In the co-main event, Arthur defeated Rea by close verdict in a outstanding Manchester vs Manchester battle to secure the European light-heavyweight title.
The stadium grew hushed for a deeply poignant homage prior to the bout as a bell ceremony tolled in remembrance of Manchester's own Hatton, who passed away 46 years old in September.
It was the first major televised match card in the city since the passing of Hatton. As the concluding sound ended, the quiet gave way to a roar of "there's just one Hatton".
The competition inside the ropes reflected the feeling. The eventual winner was floored by a significant blow squarely on the face in the second round, rising shakily to his feet on the referee's count.
But the traditional red attire of Arthur soon advanced again. On the opposite side, the opponent - in rival City blue - was damaged soon, significant bruising appearing under his face as the pair exchanged punishing blows.
Rea, twenty-seven, landed power punches but the champion, 34, fought fire with fire with effective uppercuts as the pace rarely dropped over 12 rounds.
The victor narrowly won the verdict with judges scorecards of draw, narrow lead and clearer margin, but both fighters were determined and courageous, exactly what their inspiration Hatton stood for.
