UK light heavyweight Buatsi earned a win yet unimpressive debut to life under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a judges' verdict in a tight 10-round fight at the boxing arena.
But the challenger found success, connecting with powerful single shots in a match where the approaches never quite clicked, with frequent clinching marring the action.
Two judges judged it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my best performance but what defines champions? They prevail," Buatsi commented in the ring as he was faced boos from the spectators.
The Londoner got back to winning after his initial pro loss - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Various analysts felt the challenger, thirty-one, merited the win but the contender experienced the second setback of his 28-fight career.
The Champion Earns Triumph in Uneventful Match
Buatsi's progress has slowed in recent years through contract problems and extended periods of lack of fights.
Previously predicted as the rising talent of the British fight scene, he now stands trying to achieve expectations - possibly in what seems like a ultimate opportunity - under recent support.
He began cautiously, with both competitors prepared to be aggressive in a cagey early stages.
Parker, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second fight at light heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for the favorite, who worked behind a protective stance to narrowly win the cleaner periods.
The spectators' acceptance diminished because of frequent holding, with Parker slipping to the canvas various instances during close exchanges.
Parker finished the stronger, but multiple periods were hard to judge. Nevertheless, previous titleholder the boxing analyst - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just only one stanza.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Homage Inspires Manchester Derby Fight
In the co-main event, Lyndon Arthur beat Rea by split-decision in a outstanding local rivalry contest to secure the European light heavyweight championship.
The venue fell silent for a extremely emotional tribute prior to the bout as a bell ceremony sounded in remembrance of Manchester's own Ricky Hatton, who succumbed aged 46 in recently.
It was the initial significant broadcast match card in the urban center since the passing of Hatton. As the final chime ended, the quiet gave way to a shout of "there's just one Ricky Hatton".
The competition during the bout matched the feeling. The eventual winner was floored by a left hook directly to the face in the second round, rising shakily to his footing on the eight count.
But the traditional red shorts of Arthur soon advanced again. From the other corner, Rea - in competitive blue - was injured early, heavy swelling appearing under his face as the pair landed punishing blows.
Rea, 27, connected with strong blows but Arthur, 34, responded in kind with effective uppercuts as the action rarely dropped over twelve rounds.
The victor narrowly won the result with judges scorecards of draw, close margin and 115-112, but the two athletes were determined and courageous, exactly what their hero Hatton embodied.
