British light heavyweight Buatsi made a winning yet unimpressive debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a tight 10-round contest at the Manchester venue.
But Parker found success, delivering effective clean blows in a match where the techniques didn't complement each other, with constant grabbing disrupting the contest.
The officials had it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my finest display but what do champions do? They prevail," Buatsi stated in the arena as he was met by boos from the spectators.
The British fighter got back to winning after his first professional defeat - an epic battle with Callum Smith in February - to claim a 20th career victory.
Several boxing experts believed Parker, 31, deserved the win but the contender endured the second setback of his 28-match professional journey.
Buatsi Secures Triumph in Dull Match
The fighter's advancement has stalled in recent times through management issues and long spells of inactivity.
Once tipped as the rising talent of British boxing, he now finds himself trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under new promotional backing.
He opened tentatively, with both competitors prepared to be aggressive in a tentative initial rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was making just his second fight at light-heavyweight.
By the fight's midpoint, Parker had kept it close, creating difficulties for the favorite, who operated with a solid defense to narrowly win the more effective periods.
The spectators' acceptance decreased during regular grabbing, with the challenger falling to the floor multiple occasions during grappling.
Parker finished the stronger, but many rounds were challenging to assess. Although, ex-champion the boxing analyst - commentating on the broadcast network - had it particularly wide for Parker, scoring for Buatsi just one round.
The victor advances, but with the caliber of hard hitter Benavidez, and Eastern European fighter Bivol leading the category, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Fight
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a outstanding Manchester vs Manchester battle to win the European light heavyweight belt.
The venue grew hushed for a deeply poignant tribute ahead of the contest as ten bells tolled in remembrance of local hero Hatton, who passed away 46 years old in September.
It was the first major televised boxing event in the location since Hatton's death. As the last bell ended, the quiet became a chant of "there's only one Ricky Hatton".
The action during the bout matched the feeling. Arthur was knocked down by a powerful punch squarely on the face in the second round, standing uncertainly to his footing on the referee's count.
But the red-colored attire of the fighter soon advanced again. Across the ring, Rea - in rival City blue - was damaged early, heavy swelling developing under his face as the pair exchanged hard punches.
The challenger, 27, delivered effective strikes but the champion, thirty-four, responded in kind with powerful upward punches as the intensity hardly diminished over twelve rounds.
Arthur barely secured the result with judges scorecards of draw, 115-113 and wider gap, but the two athletes were persistent and courageous, everything their inspiration the legend stood for.
