UK light heavyweight Buatsi made a winning yet unimpressive beginning to life under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a judges' verdict in a close 10-round bout at the Manchester venue.
But the challenger landed significant shots, delivering effective single shots in a fight where the styles didn't complement each other, with constant grabbing marring the fight.
The officials judged it 96-94 for to the winner, with the remaining official a 95-95.
"It wasn't my best performance but what do champions do? They win," the victor stated in the ringside as he was faced negative reactions from the spectators.
The British fighter bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts believed the challenger, 31, merited the win but the British boxer endured the second setback of his 28-bout professional journey.
Buatsi Secures Win in Slow Match
The fighter's advancement has plateaued in the past few years through contract problems and considerable time of inactivity.
Earlier forecast as the next star of UK boxing, he now stands trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He opened tentatively, with neither fighter prepared to overcommit in a calculated early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand during the bout, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for Buatsi, who worked behind a tight guard to edge the more effective periods.
The audience's tolerance decreased amid constant clinching, with Parker going down multiple occasions during clinches.
Parker closed well, but many rounds were difficult to score. However, former world champion the boxing analyst - working with Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi progresses, but with the presence of power puncher Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Homage Motivates Local Rivalry Fight
In the co-main event, Arthur beat Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to secure the European light-heavyweight championship.
The venue fell silent for a extremely emotional homage before the fight as 10 bells rang in remembrance of local hero Ricky Hatton, who died aged 46 in last month.
It was the initial significant broadcast boxing event in the city since Hatton's passing. As the concluding sound disappeared, the stillness became a shout of "there's just one Ricky Hatton".
The action within the ring matched the feeling. Arthur was sent to the canvas by a powerful punch squarely on the chin in the initial stage, standing uncertainly to his footing on the eight count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was marked up early, noticeable damage appearing under his orbital area as the duo landed powerful shots.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with effective uppercuts as the intensity rarely dropped over twelve rounds.
Arthur narrowly won the decision with official scores of draw, narrow lead and 115-112, but each competitor were persistent and courageous, all the qualities their hero the legend embodied.
