UK light heavyweight Buatsi earned a win yet disappointing beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a close 10-round bout at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling single shots in a match where the approaches didn't complement each other, with excessive holding disrupting the contest.
The scoring judges judged it 96-94 for to the winner, with the final judge a 95-95 draw.
"It wasn't my best showing but what defines champions? They succeed," the victor commented in the arena as he was faced disapproval from the crowd.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in February - to earn a 20th pro success.
Some ringside observers thought Parker, 31, merited the victory but the contender experienced the second defeat of his 28-fight career.
Buatsi Earns Win in Uneventful Match
His career development has slowed in the past few years through management issues and extended periods of inactivity.
Once tipped as the rising talent of British boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He opened tentatively, with both competitors ready to take risks in a tentative early stages.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in two years ago after damaging his hand during the bout, was making just his second appearance at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for the favorite, who worked behind a tight guard to narrowly win the better rounds.
The audience's tolerance diminished during regular grabbing, with the challenger going down various instances during close exchanges.
Parker closed well, but several stanzas were challenging to assess. Although, previous titleholder the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just a single round.
The victor progresses, but with the caliber of power puncher David Benavidez, and Russian star Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Hatton Memorial Fuels Manchester Derby Battle
In the secondary fight, Lyndon Arthur beat Bradley Rea by divided decision in a excellent all-Manchester battle to secure the continental championship.
The arena fell silent for a profoundly moving tribute before the fight as a bell ceremony tolled in remembrance of the city's native Ricky Hatton, who died at age 46 in September.
It was the first major televised boxing event in the urban center since Hatton's death. As the concluding sound disappeared, the silence became a roar of "only one Hatton".
The fighting inside the ropes equaled the feeling. The eventual winner was sent to the canvas by a powerful punch flush on the chin in the second round, standing uncertainly to his feet on the eight count.
But the traditional red attire of Arthur soon advanced again. Across the ring, the opponent - in rival City blue - was damaged quickly, heavy swelling forming under his eye as the fighters exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with effective uppercuts as the action rarely dropped over 12 rounds.
The victor barely secured the verdict with official scores of 114-114, close margin and 115-112, but each competitor were persistent and full of heart, all the qualities their inspiration Hatton embodied.
