British light heavyweight Buatsi earned a win yet unimpressive debut to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a tight ten-round fight at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a contest where the techniques never quite clicked, with constant grabbing spoiling the action.
The scoring judges scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my greatest display but what defines champions? They win," Buatsi stated in the arena as he was faced boos from the spectators.
The Londoner got back to winning after his initial pro loss - an memorable fight with Callum Smith in February - to secure a 20th pro success.
Several boxing experts believed Parker, thirty-one, should have been awarded the win but the British boxer experienced the second loss of his 28-match career.
Buatsi Earns Triumph in Slow Match
His career development has stalled in recent times through management issues and long spells of lack of fights.
Previously predicted as the next star of the British fight scene, he now stands trying to realize his potential - maybe in what appears to be a last chance - under recent support.
He opened tentatively, with both competitors prepared to be aggressive in a cagey early stages.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was participating in his second fight at light heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who utilized a solid defense to barely take the cleaner rounds.
The crowd's patience wore thin because of frequent holding, with the challenger slipping to the canvas several times during grappling.
Parker closed well, but multiple periods were challenging to assess. However, ex-champion the boxing analyst - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates Manchester Derby Contest
In the supporting bout, Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester battle to secure the European light heavyweight belt.
The stadium grew hushed for a deeply poignant memorial before the fight as ten bells tolled in remembrance of the city's native Hatton, who passed away at age 46 in last month.
It was the first major televised boxing event in the city since Hatton's death. As the concluding sound disappeared, the quiet gave way to a chant of "there's only one Hatton".
The action inside the ropes equaled the feeling. Arthur was sent to the canvas by a powerful punch directly to the jaw in the second round, rising shakily to his footing on the eight count.
But the Manchester United-red attire of the fighter soon pressed ahead again. From the other corner, the opponent - in opposing blue - was marked up soon, noticeable damage forming under his eye as the duo landed powerful shots.
Rea, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity rarely dropped over twelve rounds.
Arthur edged the result with scoring tallies of even score, close margin and 115-112, but each competitor were persistent and brave, all the qualities their idol the legend embodied.
