British light-heavyweight Buatsi earned a win yet underwhelming start to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a majority decision in a tight 10-round bout at the Manchester venue.
But the challenger found success, connecting with powerful single shots in a fight where the techniques failed to mesh, with constant grabbing disrupting the contest.
The officials judged it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my greatest performance but what do champions do? They win," the victor commented in the ringside as he was faced boos from the spectators.
The British fighter got back to winning after his first professional defeat - an memorable fight with Callum Smith in February - to earn a 20th career victory.
Several boxing experts believed the challenger, thirty-one, deserved the decision but the British boxer experienced the second loss of his 28-match professional journey.
The Champion Secures Triumph in Uneventful Affair
His career development has slowed in recent years through promotional disputes and considerable time of lack of fights.
Earlier forecast as the rising talent of the British fight scene, he now is positioned trying to fulfil that early promise - possibly in what feels like a final roll of the dice - under fresh management.
He started carefully, with neither fighter prepared to take risks in a cagey early stages.
Parker, whose sole prior loss came at super middleweight against John Ryder in 2022 after damaging his hand in the contest, was participating in his second fight at light heavyweight.
By the halfway stage, Parker had stayed in contention, making life awkward for the favorite, who worked behind a protective stance to narrowly win the better periods.
The crowd's patience wore thin because of regular grabbing, with the challenger slipping to the canvas multiple occasions during grappling.
The underdog ended stronger, but multiple periods were challenging to assess. However, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, scoring for Buatsi just a single round.
The victor progresses, but with the likes of hard hitter Benavidez, and Russian champion Bivol dominating the weight class, the journey to titles - on this evidence - still appears challenging.
Ricky Hatton Tribute Motivates Manchester Derby Contest
In the co-main event, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent all-Manchester fight to secure the European light heavyweight title.
The venue became quiet for a deeply poignant homage prior to the bout as ten bells sounded in remembrance of the city's native Ricky Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast match card in the city since Hatton's death. As the concluding sound ended, the stillness transitioned to a roar of "only one Hatton".
The fighting within the ring matched the sentiment. The eventual winner was knocked down by a significant blow squarely on the jaw in the second round, rising shakily to his feet on the eight count.
But the red-colored shorts of the fighter soon advanced again. From the other corner, the opponent - in rival City blue - was damaged quickly, significant bruising appearing under his orbital area as the pair exchanged punishing blows.
The challenger, 27, landed power punches but the champion, thirty-four, matched the intensity with stinging uppercuts as the intensity hardly diminished over the full distance.
The victor barely secured the result with official scores of draw, 115-113 and clearer margin, but the two athletes were determined and brave, all the qualities their idol the legend represented.
