UK light-heavyweight Buatsi earned a win yet underwhelming start to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a split decision in a close ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling individual punches in a contest where the techniques didn't complement each other, with constant grabbing disrupting the contest.
The officials judged it 96-94 in favor to Buatsi, with the third a even score.
"It wasn't my finest performance but what do champions do? They win," Buatsi stated in the ring as he was faced boos from the audience.
The British fighter bounced back after his maiden career setback - an memorable fight with his previous opponent in February - to secure a twentieth professional win.
Some ringside observers believed Parker, thirty-one, merited the victory but the contender endured the second setback of his 28-match professional journey.
Buatsi Secures Triumph in Uneventful Match
The fighter's advancement has stalled in recent years through contract problems and considerable time of inactivity.
Previously predicted as the future of UK boxing, he now stands trying to realize his potential - maybe in what seems like a ultimate opportunity - under fresh management.
He began cautiously, with the two boxers ready to overcommit in a cagey initial rounds.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after suffering a hand injury during the bout, was making just his second appearance at light heavyweight.
By the middle rounds, Parker had made it competitive, causing problems for Buatsi, who operated with a solid defense to narrowly win the more effective stanzas.
The audience's tolerance decreased during regular grabbing, with the challenger going down several times during grappling.
Parker closed well, but many rounds were hard to judge. Nevertheless, previous titleholder Carl Frampton - commentating on Dazn - had it particularly wide for the challenger, awarding Buatsi just a single round.
The victor advances, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the supporting bout, Lyndon Arthur defeated Rea by close verdict in a terrific Manchester vs Manchester contest to win the continental belt.
The arena grew hushed for a profoundly moving memorial before the fight as a bell ceremony sounded in honor of local hero Ricky Hatton, who died 46 years old in last month.
It was the premier televised fight night in the location since Hatton's death. As the concluding sound ended, the quiet became a chant of "there's only one Ricky Hatton".
The competition during the bout reflected the sentiment. The eventual winner was knocked down by a powerful punch squarely on the face in the initial stage, standing uncertainly to his position on the count of eight.
But the traditional red shorts of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was damaged early, significant bruising appearing under his orbital area as the fighters exchanged punishing blows.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with powerful upward punches as the action hardly diminished over the full distance.
The victor edged the verdict with scoring tallies of draw, narrow lead and 115-112, but both fighters were determined and brave, all the qualities their idol Hatton represented.
