British light-heavyweight Buatsi secured a victory yet unimpressive debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a split decision in a tight 10-round bout at the Co-op Live Arena.
But Parker found success, delivering effective single shots in a contest where the styles never quite clicked, with constant grabbing marring the action.
The scoring judges judged it 96-94 for to Buatsi, with the final judge a even score.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi said in the ring as he was met by negative reactions from the crowd.
The Londoner got back to winning after his initial pro loss - an thrilling contest with Callum Smith in last winter - to earn a 20th pro success.
Various analysts believed Parker, thirty-one, merited the decision but the Derbyshire fighter suffered the second loss of his 28-fight professional journey.
The Champion Secures Victory in Slow Affair
Buatsi's progress has slowed in the past few years through promotional disputes and extended periods of lack of fights.
Earlier forecast as the future of the British fight scene, he now stands trying to realize his potential - possibly in what feels like a final roll of the dice - under recent support.
He opened tentatively, with both competitors willing to be aggressive in a cagey early stages.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after damaging his hand mid-fight, was making just his second bout at light-heavyweight.
By the middle rounds, the underdog had made it competitive, causing problems for the favorite, who utilized a tight guard to barely take the cleaner periods.
The spectators' acceptance decreased amid regular grabbing, with the challenger going down multiple occasions during close exchanges.
Parker ended stronger, but many rounds were difficult to score. Nevertheless, ex-champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the caliber of power puncher David Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Tribute Inspires Manchester Derby Battle
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a excellent all-Manchester fight to win the European light heavyweight championship.
The stadium fell silent for a profoundly moving tribute before the fight as 10 bells sounded in memory of the city's native Hatton, who passed away 46 years old in last month.
It was the first major televised fight night in the urban center since the passing of Hatton. As the concluding sound disappeared, the quiet became a chant of "there's just one Ricky Hatton".
The fighting within the ring matched the emotion. Arthur was floored by a powerful punch directly to the jaw in the early round, rising shakily to his feet on the count of eight.
But the red-colored equipment of the fighter soon pressed ahead again. On the opposite side, Rea - in competitive blue - was damaged soon, heavy swelling appearing under his face as the pair traded powerful shots.
The challenger, 27, connected with strong blows but the champion, thirty-four, responded in kind with effective uppercuts as the pace hardly diminished over the full distance.
The victor edged the decision with judges scorecards of even score, close margin and wider gap, but each competitor were persistent and brave, exactly what their idol Hatton represented.
