British light-heavyweight Buatsi earned a win yet underwhelming debut to his career 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 ten-round contest at the Manchester venue.
But Parker had his moments, connecting with powerful clean blows in a contest where the styles failed to mesh, with excessive holding marring the action.
The scoring judges judged it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my best performance but what defines champions? They succeed," the victor said in the ring as he was greeted with disapproval from the audience.
The Londoner returned to winning ways after his first professional defeat - an epic battle with Callum Smith in February - to earn a 20th career victory.
Various analysts believed Parker, thirty-one, merited the win but the Derbyshire fighter experienced the second loss of his 28-match career.
The Champion Secures Win in Dull Match
The fighter's advancement has slowed in the past few years through management issues and extended periods of inactivity.
Previously predicted as the future of British boxing, he now stands trying to achieve expectations - maybe in what feels like a last chance - under recent support.
He opened tentatively, with the two boxers prepared to take risks in a cagey early stages.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was making just his second appearance at the higher weight class.
By the fight's midpoint, the underdog had stayed in contention, making life awkward for Buatsi, who utilized a protective stance to barely take the cleaner periods.
The crowd's patience wore thin because of constant clinching, with the challenger going down multiple occasions during clinches.
Parker ended stronger, but several stanzas were hard to judge. Although, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for the challenger, scoring for Buatsi just a single round.
The victor moves on, but with the likes of power puncher David Benavidez, and Russian star Dmitry Bivol leading the category, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Memorial Fuels Local Rivalry Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a terrific local rivalry contest to secure the European light heavyweight belt.
The venue became quiet for a deeply poignant homage prior to the bout as 10 bells rang in memory of the city's native Ricky Hatton, who succumbed 46 years old in recently.
It was the initial significant broadcast match card in the city since the passing of Hatton. As the concluding sound disappeared, the silence transitioned to a roar of "there's only one Ricky Hatton".
The competition within the ring equaled the emotion. The eventual winner was floored by a significant blow squarely on the jaw in the second round, standing uncertainly to his footing on the count of eight.
But the Manchester United-red shorts of the fighter soon came forward again. Across the ring, Rea - in opposing blue - was damaged quickly, noticeable damage developing under his eye as the fighters traded hard punches.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, matched the intensity with powerful upward punches as the action rarely dropped over twelve rounds.
The victor narrowly won the result with judges scorecards of draw, 115-113 and wider gap, but the two athletes were persistent and brave, all the qualities their inspiration Hatton embodied.
