British light heavyweight Buatsi made a winning yet disappointing beginning to his career under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a judges' verdict in a competitive 10-round fight at the Manchester venue.
But the challenger landed significant shots, delivering effective single shots in a fight where the styles never quite clicked, with frequent clinching marring the contest.
The officials judged it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my greatest display but what defines champions? They win," Buatsi commented in the ringside as he was faced negative reactions from the spectators.
The British fighter got back to winning after his maiden career setback - an epic battle with Callum Smith in last winter - to earn a twentieth professional win.
Various analysts believed Parker, 31, merited the win but the Derbyshire fighter suffered the second defeat of his 28-match professional journey.
The Champion Earns Triumph in Uneventful Match
His career development has slowed in recent times through management issues and long spells of inactivity.
Once tipped as the next star of the British fight scene, he now stands trying to achieve expectations - maybe in what appears to be a last chance - under recent support.
He started carefully, with neither fighter willing to take risks in a calculated initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after damaging his hand in the contest, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, the underdog had stayed in contention, creating difficulties for the favorite, who operated with a protective stance to narrowly win the better rounds.
The audience's tolerance diminished because of regular grabbing, with Parker slipping to the canvas various instances during grappling.
Parker closed well, but multiple periods were hard to judge. Although, former world champion Carl Frampton - commentating on Dazn - had it significantly in favor for Parker, giving Buatsi just one round.
Buatsi advances, but with the likes of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Hatton Homage Fuels All-Manchester Battle
In the supporting bout, Lyndon Arthur beat Rea by divided decision in a outstanding Manchester vs Manchester fight to win the European light heavyweight championship.
The venue fell silent for a deeply poignant homage before the fight as ten bells sounded in memory of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the final chime disappeared, the silence became a roar of "there's just one Hatton".
The competition within the ring equaled the emotion. The eventual winner was sent to the canvas by a significant blow directly to the face in the second round, standing uncertainly to his position on the referee's count.
But the traditional red attire of the fighter soon came forward again. Across the ring, Rea - in competitive blue - was damaged soon, heavy swelling developing under his orbital area as the fighters exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the intensity seldom decreased over 12 rounds.
The victor barely secured the decision with official scores of 114-114, close margin and wider gap, but each competitor were relentless and brave, all the qualities their hero the legend represented.
