British light heavyweight Buatsi earned a win yet unimpressive beginning to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a close 10-round bout at the Manchester venue.
But the challenger landed significant shots, landing some telling single shots in a match where the approaches failed to mesh, with excessive holding disrupting the contest.
The scoring judges scored it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my greatest showing but what defines champions? They prevail," Buatsi commented in the arena as he was met by disapproval from the crowd.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts thought Parker, thirty-one, merited the victory but the contender endured the second setback of his 28-fight professional journey.
Buatsi Earns Victory in Uneventful Match
The fighter's advancement has slowed in the past few years through contract problems and long spells of inactivity.
Earlier forecast as the rising talent of UK boxing, he now is positioned trying to realize his potential - possibly in what seems like a ultimate opportunity - under new promotional backing.
He started carefully, with the two boxers prepared to take risks in a calculated early stages.
The challenger, whose single earlier setback came at super middleweight against John Ryder in two years ago after breaking his hand in the contest, was making just his second fight at light-heavyweight.
By the fight's midpoint, Parker had made it competitive, making life awkward for the favorite, who utilized a protective stance to barely take the better rounds.
The audience's tolerance diminished during frequent holding, with the challenger slipping to the canvas various instances during clinches.
Parker ended stronger, but many rounds were challenging to assess. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the likes of hard hitter David Benavidez, and Russian star Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Fuels All-Manchester Contest
In the co-main event, Lyndon Arthur overcame Rea by split-decision in a outstanding local rivalry battle to win the European light-heavyweight championship.
The venue became quiet for a profoundly moving memorial prior to the bout as ten bells tolled in honor of local hero Hatton, who died at age 46 in recently.
It was the premier televised boxing event in the city since Hatton's death. As the last bell disappeared, the stillness gave way to a shout of "there's just one Ricky Hatton".
The competition during the bout equaled the feeling. The eventual winner was floored by a significant blow flush on the chin in the second round, getting up unsteadily to his position on the count of eight.
But the Manchester United-red attire of Arthur soon came forward again. From the other corner, Rea - in rival City blue - was damaged early, heavy swelling developing under his face as the fighters landed punishing blows.
The challenger, 27, landed power punches but Arthur, 34, matched the intensity with powerful upward punches as the pace rarely dropped over twelve rounds.
Arthur barely secured the decision with judges scorecards of 114-114, 115-113 and wider gap, but the two athletes were relentless and courageous, all the qualities their idol the legend embodied.
