UK light heavyweight Buatsi secured a victory yet unimpressive beginning to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a close ten-round contest at the Co-op Live Arena.
But Parker had his moments, delivering effective single shots in a match where the styles didn't complement each other, with frequent clinching disrupting the action.
The scoring judges judged it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my greatest showing but how do champions respond? They succeed," Buatsi stated in the arena as he was faced negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an epic battle with his previous opponent in February - to claim a 20th pro success.
Various analysts believed the challenger, thirty-one, should have been awarded the win but the British boxer suffered the second loss of his 28-match professional journey.
Buatsi Earns Triumph in Uneventful Affair
His career development has stalled in recent times through management issues and extended periods of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with both competitors willing to be aggressive in a calculated early stages.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after breaking his hand in the contest, was making just his second fight at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for the favorite, who worked behind a solid defense to narrowly win the better stanzas.
The spectators' acceptance decreased during constant clinching, with Parker slipping to the canvas several times during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. Nevertheless, former world champion Carl Frampton - commentating on Dazn - had it strongly leaning for the challenger, giving Buatsi just a single round.
Buatsi advances, but with the caliber of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - based on this performance - still seems difficult.
Hatton Tribute Inspires Local Rivalry Fight
In the supporting bout, Arthur overcame Bradley Rea by close verdict in a terrific all-Manchester contest to secure the European light-heavyweight belt.
The venue grew hushed for a profoundly moving homage ahead of the contest as ten bells tolled in remembrance of local hero Ricky Hatton, who passed away aged 46 in recently.
It was the initial significant broadcast fight night in the location since Hatton's death. As the last bell disappeared, the silence gave way to a roar of "there's only one Ricky Hatton".
The fighting inside the ropes equaled the feeling. The eventual winner was floored by a significant blow flush on the face in the initial stage, standing uncertainly to his position on the referee's count.
But the traditional red equipment of the fighter soon pressed ahead again. From the other corner, the opponent - in competitive blue - was injured quickly, heavy swelling appearing under his orbital area as the pair traded punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with effective uppercuts as the pace seldom decreased over the full distance.
Arthur barely secured the decision with judges scorecards of 114-114, narrow lead and clearer margin, but both fighters were persistent and brave, all the qualities their inspiration Hatton stood for.
