UK light-heavyweight Buatsi made a winning yet underwhelming beginning to life under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a split decision in a close ten-round fight at the boxing arena.
But Parker had his moments, delivering effective individual punches in a match where the approaches failed to mesh, with excessive holding spoiling the fight.
Two judges had it 96-94 in favor to the winner, with the third a even score.
"It wasn't my greatest showing but what do champions do? They prevail," Buatsi stated in the ring as he was met by negative reactions from the spectators.
The British fighter got back to winning after his maiden career setback - an thrilling contest with Callum Smith in last winter - to claim a 20th pro success.
Various analysts believed the challenger, 31, deserved the win but the Derbyshire fighter suffered the second setback of his 28-fight professional journey.
Buatsi Secures Win in Slow Encounter
The fighter's advancement has stalled in recent years through contract problems and long spells of lack of fights.
Earlier forecast as the rising talent of British boxing, he now stands trying to achieve expectations - possibly in what appears to be a last chance - under new promotional backing.
He started carefully, with both competitors willing to overcommit in a tentative initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after breaking his hand during the bout, was competing in only his second appearance at the higher weight class.
By the halfway stage, the underdog had made it competitive, creating difficulties for Buatsi, who operated with a protective stance to narrowly win the more effective stanzas.
The audience's tolerance wore thin because of constant clinching, with the challenger falling to the floor several times during close exchanges.
The underdog ended stronger, but multiple periods were challenging to assess. Nevertheless, ex-champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just one round.
The victor progresses, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - judging by this showing - still seems difficult.
Hatton Homage Inspires All-Manchester Battle
In the co-main event, Lyndon Arthur defeated Rea by divided decision in a outstanding Manchester vs Manchester fight to win the European light heavyweight championship.
The venue fell silent for a extremely emotional tribute prior to the bout as ten bells sounded in memory of the city's native Ricky Hatton, who died aged 46 in last month.
It was the premier televised match card in the city since Hatton's death. As the final chime faded, the quiet transitioned to a roar of "only one Ricky Hatton".
The competition during the bout matched the sentiment. The eventual winner was sent to the canvas by a significant blow squarely on the jaw in the initial stage, getting up unsteadily to his position on the eight count.
But the red-colored attire of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was marked up early, significant bruising forming under his face as the pair traded powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, responded in kind with stinging uppercuts as the intensity hardly diminished over the full distance.
The victor narrowly won the decision with official scores of 114-114, narrow lead and wider gap, but the two athletes were determined and full of heart, everything their hero Hatton stood for.
