UK light heavyweight Buatsi earned a win yet underwhelming beginning to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a split decision in a close ten-round bout at the Manchester venue.
But the challenger found success, connecting with powerful clean blows in a match where the approaches didn't complement each other, with frequent clinching spoiling the contest.
Two judges scored it 96-94 for to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They prevail," the victor commented in the arena as he was faced disapproval from the audience.
The British fighter returned to winning ways after his first professional defeat - an epic battle with Callum Smith in February - to claim a 20th career victory.
Several boxing experts believed the challenger, thirty-one, should have been awarded the victory but the Derbyshire fighter experienced the second defeat of his 28-bout professional journey.
Buatsi Earns Triumph in Uneventful Encounter
Buatsi's progress has slowed in the past few years through contract problems and long spells of inactivity.
Once tipped as the rising talent of British boxing, he now stands trying to achieve expectations - perhaps in what seems like a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers willing to be aggressive in a tentative early stages.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was competing in only his second fight at light-heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who utilized a tight guard to narrowly win the cleaner periods.
The spectators' acceptance diminished amid regular grabbing, with Parker falling to the floor several times during grappling.
Parker closed well, but several stanzas were challenging to assess. Nevertheless, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just one round.
The victor progresses, but with the presence of power puncher David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Hatton Memorial Fuels Local Rivalry Contest
In the secondary fight, Arthur overcame Rea by close verdict in a terrific Manchester vs Manchester contest to capture the European light heavyweight belt.
The stadium fell silent for a extremely emotional homage before the fight as ten bells sounded in remembrance of Manchester's own Hatton, who succumbed aged 46 in recently.
It was the first major televised fight night in the location since Hatton's death. As the concluding sound disappeared, the stillness gave way to a chant of "there's only one Ricky Hatton".
The competition during the bout matched the feeling. Arthur was sent to the canvas by a powerful punch squarely on the chin in the early round, standing uncertainly to his feet on the referee's count.
But the red-colored equipment of the fighter soon came forward again. Across the ring, Rea - in rival City blue - was injured soon, noticeable damage forming under his orbital area as the pair landed powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the action seldom decreased over the full distance.
Arthur barely secured the decision with official scores of draw, 115-113 and clearer margin, but each competitor were persistent and brave, everything their hero the legend represented.
