British light heavyweight Buatsi secured a victory yet underwhelming debut to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a competitive 10-round bout at the boxing arena.
But Parker landed significant shots, delivering effective individual punches in a match where the styles failed to mesh, with excessive holding marring the action.
Two judges had it 96-94 for to the winner, with the final judge a 95-95 draw.
"It wasn't my best showing but what do champions do? They succeed," Buatsi stated in the ringside as he was faced boos from the audience.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Some ringside observers believed Parker, thirty-one, deserved the victory but the Derbyshire fighter experienced the second loss of his 28-fight professional journey.
The Champion Earns Win in Slow Encounter
Buatsi's progress has slowed in recent years through management issues and long spells of inactivity.
Previously predicted as the future of British boxing, he now finds himself trying to realize his potential - perhaps in what seems like a final roll of the dice - under recent support.
He opened tentatively, with neither fighter prepared to overcommit in a calculated initial rounds.
The challenger, whose only previous defeat came at super middleweight against John Ryder in two years ago after damaging his hand during the bout, was competing in only his second fight at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for the favorite, who worked behind a protective stance to edge the better stanzas.
The spectators' acceptance diminished during constant clinching, with the challenger slipping to the canvas several times during close exchanges.
Parker finished the stronger, but several stanzas were challenging to assess. Although, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for the challenger, giving Buatsi just a single round.
Buatsi progresses, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still seems difficult.
Hatton Memorial Motivates Manchester Derby Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by divided decision in a outstanding local rivalry fight to capture the European light heavyweight belt.
The stadium became quiet for a extremely emotional memorial before the fight as 10 bells rang in honor of local hero Ricky Hatton, who died aged 46 in last month.
It was the initial significant broadcast match card in the location since Hatton's passing. As the final chime disappeared, the silence transitioned to a shout of "only one Ricky Hatton".
The action within the ring equaled the feeling. Arthur was knocked down by a left hook directly to the face in the early round, standing uncertainly to his position on the referee's count.
But the Manchester United-red shorts of the fighter soon advanced again. On the opposite side, the opponent - in rival City blue - was marked up quickly, noticeable damage developing under his eye as the fighters traded punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with powerful upward punches as the pace rarely dropped over 12 rounds.
The victor edged the decision with official scores of 114-114, close margin and 115-112, but each competitor were persistent and full of heart, everything their inspiration Hatton stood for.
