UK light heavyweight Buatsi secured a victory yet underwhelming beginning to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level likely gained him a majority decision in a tight ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective clean blows in a fight where the approaches didn't complement each other, with constant grabbing marring the fight.
Two judges judged it 96-94 to the winner, with the remaining official a even score.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi said in the ring as he was met by negative reactions from the audience.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to claim a 20th career victory.
Some ringside observers felt the challenger, thirty-one, merited the victory but the contender endured the second defeat of his 28-bout professional journey.
Buatsi Secures Win in Uneventful Affair
His career development has stalled in the past few years through contract problems and considerable time 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 final roll of the dice - under fresh management.
He began cautiously, with neither fighter ready to overcommit in a calculated early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury in the contest, was participating in his second appearance at light-heavyweight.
By the middle rounds, Parker had made it competitive, creating difficulties for the favorite, who operated with a tight guard to narrowly win the more effective rounds.
The crowd's patience diminished because of regular grabbing, with Parker slipping to the canvas multiple occasions during grappling.
The underdog ended stronger, but multiple periods were challenging to assess. Although, ex-champion the boxing analyst - commentating on the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi progresses, but with the presence of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Tribute Fuels Manchester Derby Contest
In the co-main event, Lyndon Arthur overcame Bradley Rea by divided decision in a terrific local rivalry contest to secure the European light-heavyweight championship.
The stadium fell silent for a deeply poignant homage ahead of the contest as 10 bells sounded in remembrance of the city's native Ricky Hatton, who died 46 years old in September.
It was the premier televised boxing event in the city since Hatton's passing. As the final chime faded, the quiet became a shout of "there's only one Hatton".
The competition inside the ropes equaled the sentiment. The eventual winner was knocked down by a significant blow directly to the face in the initial stage, getting up unsteadily to his position on the count of eight.
But the traditional red equipment of Arthur soon pressed ahead again. On the opposite side, the opponent - in rival City blue - was injured soon, noticeable damage developing under his eye as the pair landed punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the action rarely dropped over 12 rounds.
The victor barely secured the decision with official scores of draw, close margin and clearer margin, but both fighters were determined and courageous, everything their inspiration Hatton represented.
