UK light-heavyweight Buatsi made a winning yet unimpressive debut to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a close ten-round contest at the boxing arena.
But the challenger found success, delivering effective clean blows in a fight where the techniques didn't complement each other, with constant grabbing disrupting the contest.
The officials had it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my best performance but what do champions do? They prevail," the victor stated in the ringside as he was met by negative reactions from the crowd.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Some ringside observers believed Parker, 31, merited the decision but the Derbyshire fighter suffered the second loss of his 28-match career.
The Champion Secures Victory in Slow Encounter
The fighter's advancement has stalled in recent times through management issues and long spells of inactivity.
Previously predicted as the rising talent of the British fight scene, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under fresh management.
He began cautiously, with neither fighter willing to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was competing in only his second appearance at light heavyweight.
By the middle rounds, the underdog had made it competitive, creating difficulties for Buatsi, who worked behind a solid defense to narrowly win the more effective rounds.
The spectators' acceptance diminished during regular grabbing, with the challenger going down several times during grappling.
Parker finished the stronger, but several stanzas were hard to judge. However, ex-champion Carl Frampton - commentating on Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor moves on, but with the likes of hard hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Hatton Tribute Motivates Manchester Derby Fight
In the co-main event, Lyndon Arthur defeated Bradley Rea by divided decision in a terrific Manchester vs Manchester contest to win the European light-heavyweight title.
The arena grew hushed for a profoundly moving homage before the fight as a bell ceremony tolled in remembrance of Manchester's own Ricky Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the quiet transitioned to a chant of "there's only one Ricky Hatton".
The competition inside the ropes reflected the feeling. The eventual winner was sent to the canvas by a left hook directly to the face in the initial stage, getting up unsteadily to his position on the referee's count.
But the traditional red shorts of Arthur soon pressed ahead again. Across the ring, Rea - in rival City blue - was injured early, noticeable damage developing under his face as the pair landed powerful shots.
The challenger, twenty-seven, connected with strong blows but the champion, 34, responded in kind with effective uppercuts as the action seldom decreased over the full distance.
The victor edged the decision with official scores of even score, narrow lead and clearer margin, but both fighters were relentless and courageous, all the qualities their idol the legend embodied.
