UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a judges' verdict in a competitive ten-round bout at the boxing arena.
But the challenger landed significant shots, landing some telling single shots in a contest where the techniques failed to mesh, with excessive holding spoiling the action.
The scoring judges judged it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my best display but how do champions respond? They prevail," Buatsi said in the ringside as he was greeted with boos from the spectators.
The Londoner bounced back after his first professional defeat - an memorable fight with Callum Smith in last winter - to secure a twentieth professional win.
Some ringside observers felt the challenger, 31, deserved the decision but the British boxer experienced the second setback of his 28-bout professional journey.
Buatsi Claims Victory in Dull Encounter
The fighter's advancement has slowed in recent years through contract problems and extended periods of lack of fights.
Earlier forecast as the rising talent of UK boxing, he now stands trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter willing to overcommit in a tentative opening few rounds.
Parker, whose only previous defeat came at the lower weight class against his former opponent in 2022 after breaking his hand in the contest, was making just his second appearance at light heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who worked behind a tight guard to narrowly win the more effective rounds.
The crowd's patience decreased during constant clinching, with the challenger going down various instances during clinches.
Parker ended stronger, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - working with Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the likes of power puncher Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Homage Inspires Manchester Derby Fight
In the secondary fight, Arthur defeated Rea by close verdict in a terrific Manchester vs Manchester contest to win the European light-heavyweight title.
The venue fell silent for a profoundly moving homage before the fight as 10 bells rang in honor of local hero Ricky Hatton, who passed away 46 years old in September.
It was the initial significant broadcast boxing event in the location since Hatton's death. As the last bell ended, the stillness became a shout of "only one Ricky Hatton".
The action within the ring reflected the sentiment. The eventual winner was knocked down by a left hook squarely on the face in the early round, standing uncertainly to his position on the referee's count.
But the traditional red equipment of the fighter soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up soon, noticeable damage developing under his face as the duo landed powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the pace hardly diminished over the full distance.
Arthur narrowly won the verdict with scoring tallies of even score, 115-113 and wider gap, but the two athletes were determined and full of heart, all the qualities their idol the legend stood for.
