British light-heavyweight Buatsi earned a win yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a majority decision in a tight 10-round bout at the Co-op Live Arena.
But Parker found success, landing some telling single shots in a match where the techniques failed to mesh, with constant grabbing marring the fight.
The scoring judges had it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my best display but how do champions respond? They win," Buatsi commented in the arena as he was greeted with boos from the spectators.
The British fighter returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in February - to earn a twentieth professional win.
Some ringside observers thought the challenger, thirty-one, deserved the decision but the British boxer suffered the second setback of his 28-bout professional journey.
Buatsi Secures Victory in Uneventful Match
His career development has slowed in recent years through promotional disputes and extended periods of inactivity.
Previously predicted as the next star of British boxing, he now stands trying to fulfil that early promise - possibly in what feels like a final roll of the dice - under recent support.
He started carefully, with neither fighter prepared to be aggressive in a tentative initial rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in 2022 after suffering a hand injury mid-fight, was competing in only his second appearance at light-heavyweight.
By the middle rounds, Parker had kept it close, making life awkward for the favorite, who utilized a protective stance to edge the cleaner periods.
The spectators' acceptance wore thin during regular grabbing, with the challenger slipping to the canvas multiple occasions during clinches.
The underdog finished the stronger, but many rounds were challenging to assess. Nevertheless, previous titleholder Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Memorial Fuels All-Manchester Battle
In the secondary fight, Arthur beat Bradley Rea by divided decision in a outstanding Manchester vs Manchester battle to win the European light-heavyweight title.
The venue grew hushed for a deeply poignant homage prior to the bout as ten bells sounded in remembrance of local hero Hatton, who succumbed at age 46 in last month.
It was the premier televised match card in the location since Hatton's passing. As the last bell disappeared, the stillness became a roar of "there's only one Hatton".
The fighting within the ring matched the emotion. Arthur was knocked down by a left hook flush on the jaw in the second round, getting up unsteadily to his position on the referee's count.
But the Manchester United-red shorts of Arthur soon came forward again. On the opposite side, Rea - in opposing blue - was marked up quickly, significant bruising forming under his eye as the fighters landed powerful shots.
The challenger, 27, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the action hardly diminished over the full distance.
Arthur barely secured the result with scoring tallies of 114-114, 115-113 and wider gap, but each competitor were relentless and courageous, exactly what their hero Hatton embodied.
