British light-heavyweight Buatsi secured a victory yet disappointing start to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a split decision in a close ten-round contest at the Co-op Live Arena.
But Parker landed significant shots, delivering effective clean blows in a fight where the styles never quite clicked, with frequent clinching spoiling the fight.
Two judges judged it 96-94 to Buatsi, with the final judge a even score.
"It wasn't my greatest performance but what defines champions? They win," Buatsi stated in the ring as he was met by negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Some ringside observers believed Parker, thirty-one, merited the decision but the contender experienced the second setback of his 28-bout career.
The Champion Earns Triumph in Slow Affair
The fighter's advancement has stalled in the past few years through management issues and extended periods of inactivity.
Earlier forecast as the next star of British boxing, he now finds himself trying to achieve expectations - possibly in what feels like a last chance - under fresh management.
He began cautiously, with neither fighter willing to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second appearance at light-heavyweight.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who operated with a protective stance to narrowly win the better rounds.
The spectators' acceptance decreased during regular grabbing, with the challenger falling to the floor various instances during clinches.
The underdog ended stronger, but multiple periods were hard to judge. Although, former world champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Homage Inspires Manchester Derby Fight
In the supporting bout, Arthur defeated Rea by close verdict in a outstanding Manchester vs Manchester contest to secure the European light heavyweight championship.
The stadium grew hushed for a profoundly moving homage prior to the bout as 10 bells rang in honor of Manchester's own Ricky Hatton, who succumbed aged 46 in last month.
It was the premier televised boxing event in the urban center since Hatton's death. As the last bell faded, the silence became a chant of "there's only one Ricky Hatton".
The action within the ring reflected the sentiment. Arthur was knocked down by a significant blow flush on the chin in the initial stage, getting up unsteadily to his feet on the referee's count.
But the traditional red attire of Arthur soon came forward again. From the other corner, Rea - in rival City blue - was injured early, heavy swelling forming under his eye as the pair traded punishing blows.
The challenger, 27, landed power punches but Arthur, thirty-four, matched the intensity with powerful upward punches as the intensity seldom decreased over twelve rounds.
Arthur edged the result with judges scorecards of draw, 115-113 and clearer margin, but the two athletes were persistent and full of heart, everything their inspiration the legend stood for.
