British light heavyweight Buatsi made a winning yet underwhelming beginning to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a split decision in a competitive ten-round bout at the Manchester venue.
But the challenger found success, landing some telling individual punches in a contest where the techniques failed to mesh, with frequent clinching marring the contest.
The officials scored it 96-94 to the winner, with the remaining official a 95-95.
"It wasn't my best showing but how do champions respond? They win," Buatsi commented in the ringside as he was faced negative reactions from the crowd.
The British fighter bounced back after his first professional defeat - an memorable fight with his previous opponent in February - to claim a 20th pro success.
Various analysts felt the challenger, 31, merited the win but the British boxer suffered the second setback of his 28-match professional journey.
The Champion Claims Triumph in Uneventful Encounter
His career development has plateaued in recent years through promotional disputes and long spells of inactivity.
Earlier forecast as the next star of British boxing, he now is positioned trying to achieve expectations - maybe in what appears to be a last chance - under fresh management.
He opened tentatively, with the two boxers willing to overcommit in a cagey early stages.
Parker, whose sole prior loss came at super-middleweight against his former opponent in 2022 after suffering a hand injury mid-fight, was competing in only his second bout at light-heavyweight.
By the middle rounds, the underdog had made it competitive, making life awkward for the favorite, who utilized a protective stance to barely take the more effective periods.
The audience's tolerance diminished amid frequent holding, with Parker going down multiple occasions during clinches.
The underdog closed well, but many rounds were challenging to assess. Nevertheless, ex-champion Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just one round.
The victor progresses, but with the likes of power puncher David Benavidez, and Russian star Bivol dominating the weight class, the road to world glory - judging by this showing - still appears challenging.
Hatton Tribute Motivates All-Manchester Battle
In the secondary fight, Lyndon Arthur defeated Rea by split-decision in a outstanding local rivalry contest to secure the European light-heavyweight title.
The stadium became quiet for a deeply poignant memorial before the fight as a bell ceremony sounded in memory of local hero Ricky Hatton, who passed away 46 years old in September.
It was the initial significant broadcast boxing event in the city since Hatton's death. As the concluding sound faded, the silence became a roar of "there's just one Ricky Hatton".
The action within the ring equaled the feeling. The eventual winner was floored by a left hook directly to the jaw in the initial stage, standing uncertainly to his position on the eight count.
But the traditional red shorts of Arthur soon pressed ahead again. On the opposite side, Rea - in rival City blue - was marked up early, noticeable damage forming under his eye as the duo traded hard punches.
Rea, 27, connected with strong blows but Arthur, 34, matched the intensity with effective uppercuts as the intensity hardly diminished over the full distance.
The victor edged the decision with scoring tallies of 114-114, narrow lead and wider gap, but the two athletes were relentless and full of heart, all the qualities their idol the legend embodied.
