UK light-heavyweight Buatsi secured a victory yet unimpressive start to his career under fresh promotional backing 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 tight 10-round bout at the boxing arena.
But the challenger found success, connecting with powerful clean blows in a contest where the approaches never quite clicked, with frequent clinching disrupting the contest.
The officials had it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best showing but what defines champions? They succeed," the victor stated in the ring as he was greeted with boos from the crowd.
The British fighter got back to winning after his maiden career setback - an memorable fight with Callum Smith in February - to earn a twentieth professional win.
Some ringside observers thought Parker, 31, deserved the win but the British boxer suffered the second setback of his 28-fight career.
Buatsi Earns Triumph in Uneventful Match
Buatsi's progress has stalled in recent years through contract problems and extended periods of inactivity.
Earlier forecast as the next star of UK boxing, he now is positioned trying to realize his potential - perhaps in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with both competitors ready to overcommit in a cagey early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was making just his second fight at the higher weight class.
By the middle rounds, the underdog had made it competitive, making life awkward for Buatsi, who utilized a tight guard to edge the better stanzas.
The spectators' acceptance wore thin during frequent holding, with Parker slipping to the canvas multiple occasions during clinches.
Parker finished the stronger, but several stanzas were challenging to assess. However, previous titleholder the boxing analyst - commentating on Dazn - had it significantly in favor for the challenger, scoring for Buatsi just one round.
The victor progresses, but with the presence of power puncher Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Homage Motivates All-Manchester Battle
In the supporting bout, Lyndon Arthur overcame Bradley Rea by divided decision in a outstanding all-Manchester fight to capture the European light-heavyweight championship.
The stadium became quiet for a extremely emotional homage before the fight as a bell ceremony rang in honor of Manchester's own Ricky Hatton, who passed away aged 46 in September.
It was the first major televised match card in the city since Hatton's death. As the concluding sound disappeared, the silence transitioned to a chant of "there's only one Ricky Hatton".
The action inside the ropes reflected the sentiment. The eventual winner was floored by a significant blow directly to the chin in the initial stage, standing uncertainly to his position on the eight count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. On the opposite side, Rea - in competitive blue - was damaged soon, significant bruising forming under his face as the pair exchanged hard punches.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with stinging uppercuts as the intensity seldom decreased over twelve rounds.
The victor edged the verdict with scoring tallies of even score, 115-113 and clearer margin, but both fighters were determined and courageous, exactly what their inspiration Hatton embodied.
