UK light-heavyweight Buatsi earned a win yet unimpressive beginning to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a majority decision in a close 10-round contest at the Manchester venue.
But the challenger had his moments, delivering effective clean blows in a contest where the techniques didn't complement each other, with excessive holding marring the fight.
Two judges scored it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my best performance but how do champions respond? They prevail," the victor said in the ringside as he was faced boos from the crowd.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to earn a 20th career victory.
Various analysts felt the challenger, thirty-one, should have been awarded the win but the British boxer suffered the second defeat of his 28-match professional journey.
Buatsi Secures Victory in Slow Encounter
Buatsi's progress has slowed in recent times through management issues and considerable time of lack of fights.
Earlier forecast as the rising talent of the British fight scene, he now stands trying to achieve expectations - perhaps in what feels like a last chance - under recent support.
He opened tentatively, with both competitors ready to overcommit in a calculated initial rounds.
Parker, whose only previous defeat came at super-middleweight against his former opponent in two years ago after damaging his hand during the bout, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had stayed in contention, causing problems for Buatsi, who worked behind a tight guard to narrowly win the more effective stanzas.
The audience's tolerance wore thin because of frequent holding, with Parker slipping to the canvas several times during clinches.
The underdog ended stronger, but multiple periods were difficult to score. However, former world champion the boxing analyst - commentating on Dazn - had it particularly wide for the challenger, scoring for Buatsi just one round.
The victor advances, but with the caliber of heavy hitter David Benavidez, and Russian star Bivol ruling the division, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the co-main event, Arthur overcame Bradley Rea by divided decision in a outstanding Manchester vs Manchester contest to capture the European light-heavyweight title.
The venue became quiet for a deeply poignant homage prior to the bout as ten bells sounded in honor of local hero Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast fight night in the location since the passing of Hatton. As the last bell ended, the stillness became a roar of "there's just one Ricky Hatton".
The fighting during the bout matched the sentiment. The eventual winner was sent to the canvas by a significant blow flush on the jaw in the second round, standing uncertainly to his position on the eight count.
But the Manchester United-red attire of the fighter soon pressed ahead again. On the opposite side, Rea - in rival City blue - was injured soon, noticeable damage appearing under his face as the pair landed punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with stinging uppercuts as the action seldom decreased over the full distance.
The victor edged the result with official scores of 114-114, close margin and wider gap, but the two athletes were relentless and brave, all the qualities their inspiration the legend embodied.
