British light-heavyweight Buatsi secured a victory yet disappointing debut to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a close ten-round contest at the Manchester venue.
But the challenger landed significant shots, landing some telling clean blows in a contest where the approaches never quite clicked, with frequent clinching disrupting the fight.
The scoring judges had it 96-94 in favor to Buatsi, with the remaining official a 95-95.
"It wasn't my best display but what defines champions? They succeed," Buatsi commented in the ring as he was faced disapproval from the audience.
The Londoner bounced back after his first professional defeat - an epic battle with his previous opponent in February - to secure a twentieth professional win.
Some ringside observers believed Parker, thirty-one, merited the victory but the contender experienced the second setback of his 28-match career.
The Champion Secures Victory in Uneventful Encounter
The fighter's advancement has slowed in recent years through management issues and long spells of lack of fights.
Once tipped as the next star of UK boxing, he now finds himself trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under recent support.
He started carefully, with the two boxers ready to take risks in a tentative opening few rounds.
Parker, whose only previous defeat came at super-middleweight against his former opponent in 2022 after breaking his hand mid-fight, was participating in his second fight at the higher weight class.
By the fight's midpoint, Parker had made it competitive, making life awkward for Buatsi, who operated with a protective stance to barely take the more effective periods.
The spectators' acceptance decreased because of constant clinching, with Parker falling to the floor several times during clinches.
The underdog ended stronger, but multiple periods were challenging to assess. However, former world champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, awarding Buatsi just a single round.
The victor moves on, but with the likes of hard hitter David Benavidez, and Russian champion Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Hatton Homage Inspires All-Manchester Contest
In the supporting bout, Arthur overcame Rea by close verdict in a outstanding all-Manchester contest to secure the European light-heavyweight belt.
The venue grew hushed for a extremely emotional tribute prior to the bout as 10 bells rang in memory of the city's native Ricky Hatton, who died 46 years old in September.
It was the initial significant broadcast fight night in the location since Hatton's death. As the last bell ended, the silence gave way to a chant of "only one Ricky Hatton".
The action inside the ropes equaled the feeling. The eventual winner was knocked down by a left hook flush on the jaw in the initial stage, getting up unsteadily to his feet on the eight count.
But the red-colored shorts of the fighter soon advanced again. On the opposite side, the opponent - in rival City blue - was marked up soon, noticeable damage developing under his eye as the fighters landed powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the intensity rarely dropped over 12 rounds.
Arthur barely secured the decision with official scores of even score, narrow lead and wider gap, but both fighters were relentless and brave, all the qualities their idol the legend embodied.
