British light-heavyweight Buatsi secured a victory yet unimpressive start to life under fresh promotional backing 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 competitive 10-round bout at the Manchester venue.
But the challenger found success, connecting with powerful single shots in a fight where the styles failed to mesh, with frequent clinching spoiling the action.
The officials had it 96-94 in favor to the winner, with the remaining official a 95-95.
"It wasn't my finest display but what defines champions? They win," the victor stated in the arena as he was greeted with disapproval from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in February - to claim a 20th pro success.
Some ringside observers believed Parker, thirty-one, deserved the victory but the contender suffered the second loss of his 28-bout career.
Buatsi Secures Triumph in Slow Encounter
Buatsi's progress has slowed in the past few years through contract problems and considerable time of inactivity.
Once tipped as the future of the British fight scene, he now stands trying to achieve expectations - maybe in what appears to be a final roll of the dice - under new promotional backing.
He opened tentatively, with neither fighter willing to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was participating in his second appearance at the higher weight class.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who utilized a tight guard to narrowly win the more effective stanzas.
The audience's tolerance wore thin amid frequent holding, with the challenger slipping to the canvas multiple occasions during clinches.
Parker closed well, but many rounds were hard to judge. Although, ex-champion Carl Frampton - working with the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
The victor progresses, but with the likes of heavy hitter David Benavidez, and Russian star Bivol ruling the division, the road to world glory - judging by this showing - still seems difficult.
Hatton Memorial Motivates All-Manchester Fight
In the supporting bout, Arthur beat Bradley Rea by divided decision in a outstanding Manchester vs Manchester contest to win the continental title.
The venue became quiet for a extremely emotional homage before the fight as ten bells tolled in honor of Manchester's own Ricky Hatton, who succumbed aged 46 in recently.
It was the premier televised fight night in the city since Hatton's death. As the last bell ended, the stillness transitioned to a roar of "there's only one Hatton".
The fighting inside the ropes matched the feeling. The eventual winner was knocked down by a significant blow squarely on the face in the initial stage, standing uncertainly to his feet on the count of eight.
But the Manchester United-red attire of Arthur soon pressed ahead again. Across the ring, the opponent - in rival City blue - was marked up early, noticeable damage appearing under his face as the fighters exchanged hard punches.
The challenger, 27, connected with strong blows but Arthur, thirty-four, responded in kind with effective uppercuts as the pace seldom decreased over the full distance.
Arthur barely secured the verdict with scoring tallies of 114-114, narrow lead and clearer margin, but each competitor were relentless and courageous, all the qualities their idol the legend embodied.
