UK light-heavyweight Buatsi earned a win yet underwhelming beginning to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a majority decision in a tight 10-round bout at the boxing arena.
But Parker had his moments, landing some telling individual punches in a contest where the approaches failed to mesh, with frequent clinching disrupting the fight.
The officials had it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my best performance but what do champions do? They prevail," Buatsi said in the ring as he was met by disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an epic battle with Callum Smith in last winter - to claim a 20th career victory.
Several boxing experts thought Parker, 31, should have been awarded the victory but the Derbyshire fighter endured the second loss of his 28-fight career.
Buatsi Earns Win in Uneventful Encounter
The fighter's advancement has stalled in recent years through contract problems and long spells of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now stands trying to achieve expectations - maybe in what seems like a last chance - under recent support.
He started carefully, with the two boxers prepared to be aggressive in a cagey opening few rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was making just his second bout at light heavyweight.
By the fight's midpoint, the underdog had stayed in contention, making life awkward for the favorite, who worked behind a solid defense to barely take the more effective stanzas.
The audience's tolerance decreased because of regular grabbing, with the challenger slipping to the canvas various instances during grappling.
Parker finished the stronger, but many rounds were difficult to score. Nevertheless, previous titleholder the boxing analyst - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just a single round.
The victor moves on, but with the presence of heavy hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still appears challenging.
Hatton Tribute Inspires All-Manchester Battle
In the supporting bout, Arthur defeated Bradley Rea by divided decision in a terrific Manchester vs Manchester contest to win the European light heavyweight championship.
The venue grew hushed for a deeply poignant memorial before the fight as 10 bells tolled in honor of the city's native Hatton, who passed away 46 years old in last month.
It was the premier televised fight night in the urban center since the passing of Hatton. As the last bell disappeared, the stillness became a chant of "only one Ricky Hatton".
The fighting within the ring matched the feeling. Arthur was knocked down by a significant blow flush on the face in the second round, getting up unsteadily to his feet on the eight count.
But the Manchester United-red shorts of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was damaged early, heavy swelling developing under his eye as the duo exchanged hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, fought fire with fire with effective uppercuts as the action hardly diminished over twelve rounds.
Arthur narrowly won the result with judges scorecards of even score, narrow lead and wider gap, but each competitor were relentless and brave, everything their idol Hatton represented.
