UK light-heavyweight Buatsi earned a win yet unimpressive beginning to his career under new promoters with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's activity level appeared to earn him a judges' verdict in a close ten-round contest at the Manchester venue.
But the challenger found success, landing some telling clean blows in a contest where the styles failed to mesh, with frequent clinching marring the contest.
Two judges had it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best display but how do champions respond? They win," the victor stated in the ring as he was greeted with boos from the spectators.
The British fighter bounced back after his initial pro loss - an memorable fight with Callum Smith in February - to earn a twentieth professional win.
Various analysts felt Parker, 31, deserved the victory but the Derbyshire fighter experienced the second loss of his 28-bout career.
Buatsi Claims Win in Slow Affair
Buatsi's progress has slowed in the past few years through promotional disputes and extended periods of inactivity.
Once tipped as the rising talent of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a final roll of the dice - under recent support.
He opened tentatively, with the two boxers prepared to overcommit in a tentative early stages.
Parker, whose only previous defeat came at super-middleweight against John Ryder in 2022 after damaging his hand in the contest, was making just his second fight at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for Buatsi, who utilized a solid defense to barely take the better periods.
The crowd's patience wore thin amid frequent holding, with the challenger falling to the floor various instances during grappling.
Parker finished the stronger, but multiple periods were difficult to score. Although, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just a single round.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Memorial Fuels Manchester Derby Contest
In the secondary fight, Lyndon Arthur beat Bradley Rea by divided decision in a excellent local rivalry contest to win the European light heavyweight belt.
The stadium fell silent for a deeply poignant homage prior to the bout as 10 bells rang in memory of local hero Ricky Hatton, who died at age 46 in September.
It was the premier televised boxing event in the location since Hatton's death. As the last bell disappeared, the silence became a roar of "there's only one Ricky Hatton".
The action during the bout matched the emotion. Arthur was sent to the canvas by a significant blow directly to the chin in the second round, standing uncertainly to his position on the count of eight.
But the red-colored shorts of the fighter soon came forward again. On the opposite side, the opponent - in competitive blue - was injured early, significant bruising appearing under his orbital area as the duo landed hard punches.
Rea, twenty-seven, connected with strong blows but the champion, 34, fought fire with fire with effective uppercuts as the action hardly diminished over the full distance.
Arthur edged the decision with official scores of 114-114, 115-113 and clearer margin, but each competitor were determined and full of heart, exactly what their idol Hatton represented.
