UK light-heavyweight Buatsi earned a win yet underwhelming debut to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a tight 10-round bout at the boxing arena.
But Parker had his moments, connecting with powerful single shots in a contest where the approaches didn't complement each other, with frequent clinching spoiling the contest.
The scoring judges judged it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my finest display but what defines champions? They prevail," the victor said in the ring as he was greeted with boos from the spectators.
The Londoner returned to winning ways after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts believed Parker, thirty-one, should have been awarded the victory but the contender experienced the second defeat of his 28-bout professional journey.
The Champion Secures Triumph in Dull Encounter
The fighter's advancement has slowed in recent years through management issues and considerable time of lack of fights.
Once tipped as the rising talent of British boxing, he now is positioned trying to realize his potential - perhaps in what appears to be a last chance - under fresh management.
He opened tentatively, with both competitors prepared to overcommit in a cagey opening few rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after damaging his hand in the contest, was competing in only his second fight at light heavyweight.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who worked behind a tight guard to barely take the more effective periods.
The audience's tolerance wore thin during constant clinching, with Parker going down multiple occasions during clinches.
The underdog closed well, but several stanzas were challenging to assess. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it particularly wide for Parker, scoring for Buatsi just one round.
Buatsi advances, but with the caliber of hard hitter David Benavidez, and Russian star Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Hatton Tribute Motivates All-Manchester Contest
In the supporting bout, Arthur beat Rea by split-decision in a outstanding local rivalry contest to capture the continental championship.
The arena fell silent for a extremely emotional tribute ahead of the contest as ten bells sounded in memory of Manchester's own Hatton, who succumbed 46 years old in last month.
It was the first major televised match card in the city since Hatton's death. As the concluding sound faded, the stillness transitioned to a chant of "there's just one Ricky Hatton".
The fighting inside the ropes equaled the sentiment. The eventual winner was floored by a left hook squarely on the face in the early round, standing uncertainly to his feet on the count of eight.
But the red-colored attire of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was damaged early, noticeable damage forming under his eye as the fighters exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, thirty-four, responded in kind with effective uppercuts as the intensity rarely dropped over twelve rounds.
The victor barely secured the verdict with judges scorecards of even score, close margin and clearer margin, but the two athletes were persistent and brave, all the qualities their hero the legend stood for.
