UK light heavyweight Buatsi secured a victory yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a competitive 10-round fight at the Manchester venue.
But the challenger had his moments, connecting with powerful individual punches in a fight where the styles failed to mesh, with excessive holding disrupting the contest.
The officials judged it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my best performance but what do champions do? They win," Buatsi commented in the arena as he was greeted with negative reactions from the audience.
The British fighter returned to winning ways after his first professional defeat - an thrilling contest with Callum Smith in February - to secure a 20th pro success.
Some ringside observers believed Parker, 31, merited the decision but the contender suffered the second setback of his 28-match professional journey.
The Champion Claims Triumph in Slow Match
Buatsi's progress has stalled in recent times through contract problems and considerable time of inactivity.
Once tipped as the rising talent of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter ready to overcommit in a tentative opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after suffering a hand injury during the bout, was competing in only his second fight at light heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who utilized a solid defense to edge the more effective rounds.
The crowd's patience decreased amid frequent holding, with Parker slipping to the canvas several times during grappling.
Parker ended stronger, but multiple periods were hard to judge. However, ex-champion the boxing analyst - working with Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor advances, but with the likes of heavy hitter David Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Homage Inspires Local Rivalry Fight
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a outstanding all-Manchester contest to win the continental belt.
The stadium fell silent for a extremely emotional memorial ahead of the contest as ten bells rang in memory of local hero Ricky Hatton, who succumbed aged 46 in last month.
It was the first major televised boxing event in the urban center since Hatton's death. As the concluding sound faded, the quiet gave way to a chant of "there's just one Hatton".
The competition within the ring matched the emotion. Arthur was floored by a powerful punch flush on the chin in the second round, standing uncertainly to his position on the eight count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was damaged early, significant bruising developing under his orbital area as the duo exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, 34, responded in kind with stinging uppercuts as the intensity rarely dropped over 12 rounds.
The victor edged the result with judges scorecards of 114-114, close margin and wider gap, but both fighters were persistent and brave, exactly what their hero Hatton embodied.
