British light heavyweight Buatsi earned a win yet unimpressive beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a close 10-round bout at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective clean blows in a fight where the techniques didn't complement each other, with excessive holding disrupting the fight.
Two judges judged it 96-94 for to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest performance but what defines champions? They win," the victor commented in the ringside as he was greeted with disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a 20th pro success.
Some ringside observers thought the challenger, 31, deserved the victory but the contender endured the second setback of his 28-match career.
Buatsi Claims Win in Slow Encounter
His career development has stalled in the past few years through promotional disputes and long spells of inactivity.
Previously predicted as the rising talent of the British fight scene, he now finds himself trying to realize his potential - maybe in what appears to be a last chance - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a tentative opening few rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand during the bout, was participating in his second appearance at light-heavyweight.
By the middle rounds, the underdog had kept it close, causing problems for Buatsi, who operated with a protective stance to edge the cleaner periods.
The spectators' acceptance decreased amid frequent holding, with the challenger slipping to the canvas several times during grappling.
The underdog closed well, but many rounds were difficult to score. However, previous titleholder the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
The victor progresses, but with the presence of power puncher David Benavidez, and Russian star Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Tribute Motivates Local Rivalry Contest
In the supporting bout, Arthur defeated Rea by divided decision in a outstanding all-Manchester contest to secure the European light heavyweight championship.
The venue became quiet for a deeply poignant homage prior to the bout as ten bells sounded in honor of the city's native Hatton, who passed away 46 years old in September.
It was the initial significant broadcast match card in the location since the passing of Hatton. As the final chime disappeared, the quiet gave way to a shout of "there's just one Ricky Hatton".
The action within the ring equaled the sentiment. Arthur was knocked down by a significant blow directly to the jaw in the initial stage, getting up unsteadily to his position on the count of eight.
But the traditional red shorts of the fighter soon advanced again. On the opposite side, the opponent - in competitive blue - was damaged quickly, heavy swelling appearing under his orbital area as the pair traded powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, fought fire with fire with powerful upward punches as the action hardly diminished over twelve rounds.
Arthur narrowly won the verdict with scoring tallies of draw, narrow lead and 115-112, but each competitor were determined and brave, exactly what their idol the legend represented.
