UK light heavyweight Buatsi made a winning yet disappointing debut to life under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a majority decision in a tight 10-round fight at the boxing arena.
But Parker found success, delivering effective single shots in a fight where the approaches never quite clicked, with frequent clinching spoiling the action.
The officials scored it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest showing but how do champions respond? They prevail," the victor commented in the ringside as he was faced negative reactions from the spectators.
The British fighter got back to winning after his first professional defeat - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Several boxing experts believed Parker, thirty-one, merited the win but the contender experienced the second setback of his 28-bout professional journey.
Buatsi Earns Win in Slow Affair
Buatsi's progress has plateaued in the past few years through management issues and extended periods of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what feels like a last chance - under new promotional backing.
He opened tentatively, with neither fighter ready to overcommit in a tentative early stages.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after breaking his hand during the bout, was competing in only his second appearance at light heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for the favorite, who utilized a tight guard to barely take the better rounds.
The audience's tolerance wore thin because of frequent holding, with Parker slipping to the canvas various instances during clinches.
Parker ended stronger, but many rounds were difficult to score. Although, former world champion the boxing analyst - commentating on Dazn - had it particularly wide for Parker, giving Buatsi just a single round.
Buatsi advances, but with the presence of hard hitter Benavidez, and Eastern European fighter Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Homage Inspires All-Manchester Fight
In the co-main event, Arthur defeated Bradley Rea by close verdict in a terrific Manchester vs Manchester battle to secure the European light-heavyweight championship.
The stadium grew hushed for a extremely emotional tribute ahead of the contest as 10 bells sounded in memory of local hero Hatton, who passed away aged 46 in last month.
It was the first major televised match card in the city since Hatton's death. As the final chime disappeared, the stillness gave way to a roar of "only one Ricky Hatton".
The action during the bout reflected the sentiment. Arthur was sent to the canvas by a significant blow flush on the chin in the second round, standing uncertainly to his footing on the count of eight.
But the red-colored shorts of the fighter soon pressed ahead again. From the other corner, the opponent - in rival City blue - was marked up quickly, significant bruising developing under his orbital area as the duo landed powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, matched the intensity with powerful upward punches as the action seldom decreased over the full distance.
Arthur edged the verdict with official scores of 114-114, 115-113 and wider gap, but both fighters were relentless and brave, exactly what their idol the legend stood for.
