British light heavyweight Buatsi earned a win yet underwhelming debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a tight 10-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful individual punches in a match where the approaches never quite clicked, with constant grabbing spoiling the action.
The scoring judges had it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best showing but how do champions respond? They prevail," the victor said in the ring as he was met by negative reactions from the audience.
The British fighter got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to secure a twentieth professional win.
Some ringside observers felt Parker, thirty-one, should have been awarded the win but the contender experienced the second loss of his 28-bout career.
Buatsi Secures Win in Uneventful Affair
His career development has stalled in the past few years through management issues and long spells of lack of fights.
Previously predicted as the rising talent of UK boxing, he now finds himself trying to achieve expectations - perhaps in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter willing to take risks in a tentative initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after suffering a hand injury in the contest, was making just his second appearance at light heavyweight.
By the halfway stage, the underdog had made it competitive, creating difficulties for the favorite, who utilized a protective stance to narrowly win the better periods.
The spectators' acceptance decreased because of constant clinching, with the challenger falling to the floor multiple occasions during close exchanges.
The underdog ended stronger, but multiple periods were difficult to score. However, ex-champion the boxing analyst - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
The victor advances, but with the caliber of heavy hitter David Benavidez, and Russian champion Dmitry Bivol leading the category, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Tribute Inspires Local Rivalry Fight
In the co-main event, Lyndon Arthur overcame Bradley Rea by divided decision in a outstanding all-Manchester fight to secure the continental championship.
The venue fell silent for a profoundly moving tribute before the fight as a bell ceremony rang in memory of the city's native Hatton, who succumbed aged 46 in recently.
It was the premier televised boxing event in the city since Hatton's death. As the concluding sound faded, the quiet transitioned to a shout of "there's just one Ricky Hatton".
The action during the bout reflected the emotion. Arthur was sent to the canvas by a significant blow squarely on the face in the second round, standing uncertainly to his footing on the eight count.
But the Manchester United-red equipment of Arthur soon came forward again. From the other corner, the opponent - in opposing blue - was injured quickly, noticeable damage appearing under his face as the pair traded powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, 34, responded in kind with stinging uppercuts as the pace seldom decreased over the full distance.
Arthur barely secured the decision with official scores of draw, 115-113 and 115-112, but the two athletes were relentless and brave, exactly what their inspiration Hatton embodied.
