UK light heavyweight Buatsi earned a win yet unimpressive start to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a split decision in a tight ten-round bout at the Co-op Live Arena.
But the challenger found success, connecting with powerful single shots in a fight where the styles never quite clicked, with excessive holding marring the fight.
The scoring judges scored it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest performance but what defines champions? They win," Buatsi stated in the ringside as he was faced disapproval from the audience.
The British fighter got back to winning after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a 20th career victory.
Some ringside observers felt the challenger, thirty-one, should have been awarded the decision but the Derbyshire fighter experienced the second setback of his 28-fight professional journey.
The Champion Secures Victory in Uneventful Encounter
The fighter's advancement has stalled in the past few years through promotional disputes and considerable time of inactivity.
Earlier forecast as the rising talent of UK boxing, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with neither fighter prepared to overcommit in a calculated opening few rounds.
The challenger, whose single earlier setback came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was making just his second fight at light heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for Buatsi, who utilized a solid defense to narrowly win the more effective periods.
The audience's tolerance wore thin during regular grabbing, with Parker falling to the floor various instances during clinches.
The underdog finished the stronger, but many rounds were hard to judge. However, previous titleholder the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just only one stanza.
The victor progresses, but with the likes of power puncher David Benavidez, and Russian star Bivol ruling the division, the path to championship success - on this evidence - still looks steep.
Hatton Memorial Inspires All-Manchester Battle
In the secondary fight, Arthur beat Bradley Rea by divided decision in a excellent Manchester vs Manchester fight to capture the European light-heavyweight championship.
The arena grew hushed for a deeply poignant homage before the fight as ten bells tolled in honor of Manchester's own Hatton, who succumbed 46 years old in September.
It was the premier televised match card in the city since Hatton's passing. As the concluding sound disappeared, the quiet transitioned to a roar of "only one Hatton".
The competition during the bout matched the emotion. Arthur was sent to the canvas by a significant blow directly to the chin in the early round, getting up unsteadily to his footing on the referee's count.
But the traditional red attire of the fighter soon pressed ahead again. On the opposite side, Rea - in competitive blue - was damaged soon, heavy swelling developing under his face as the fighters landed hard punches.
The challenger, twenty-seven, landed power punches but Arthur, thirty-four, matched the intensity with powerful upward punches as the action hardly diminished over twelve rounds.
Arthur edged the decision with judges scorecards of draw, 115-113 and wider gap, but the two athletes were relentless and brave, all the qualities their idol the legend embodied.
