UK light-heavyweight Buatsi earned a win yet unimpressive beginning to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a majority decision in a tight ten-round bout at the boxing arena.
But Parker had his moments, delivering effective individual punches in a match where the approaches didn't complement each other, with excessive holding marring the fight.
The scoring judges judged it 96-94 for to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest performance but what do champions do? They win," Buatsi commented in the ringside as he was met by disapproval from the crowd.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in last winter - to earn a 20th pro success.
Various analysts believed Parker, thirty-one, should have been awarded the win but the Derbyshire fighter experienced the second setback of his 28-bout career.
Buatsi Claims Triumph in Slow Encounter
The fighter's advancement has plateaued in recent times through promotional disputes and extended periods of lack of fights.
Previously predicted as the future of British boxing, he now stands trying to achieve expectations - maybe in what feels like a last chance - under new promotional backing.
He began cautiously, with both competitors prepared to be aggressive in a cagey early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand in the contest, was participating in his second appearance at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, making life awkward for the favorite, who operated with a tight guard to edge the more effective rounds.
The crowd's patience diminished during regular grabbing, with the challenger slipping to the canvas several times during grappling.
The underdog ended stronger, but several stanzas were difficult to score. Although, previous titleholder the boxing analyst - working with Dazn - had it significantly in favor for the challenger, giving Buatsi just a single round.
Buatsi advances, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Tribute Motivates All-Manchester Battle
In the supporting bout, Arthur defeated Rea by divided decision in a excellent all-Manchester fight to capture the European light-heavyweight title.
The arena fell silent for a deeply poignant homage before the fight as ten bells tolled in honor of local hero Ricky Hatton, who passed away aged 46 in September.
It was the premier televised fight night in the city since the passing of Hatton. As the final chime disappeared, the quiet became a shout of "there's just one Hatton".
The fighting within the ring equaled the feeling. The eventual winner was knocked down by a left hook flush on the jaw in the second round, rising shakily to his position on the eight count.
But the red-colored equipment of Arthur soon advanced again. On the opposite side, Rea - in opposing blue - was damaged quickly, noticeable damage forming under his face as the fighters landed powerful shots.
The challenger, 27, connected with strong blows but Arthur, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over twelve rounds.
Arthur edged the decision with judges scorecards of even score, narrow lead and clearer margin, but both fighters were persistent and full of heart, exactly what their inspiration the legend stood for.
