British light heavyweight Buatsi earned a win yet underwhelming debut to life 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 judges' verdict in a tight ten-round fight at the boxing arena.
But the challenger had his moments, connecting with powerful individual punches in a contest where the approaches didn't complement each other, with frequent clinching spoiling the action.
Two judges had it 96-94 to the winner, with the final judge a 95-95.
"It wasn't my best display but what defines champions? They win," the victor commented in the ringside as he was met by disapproval from the crowd.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to claim a 20th career victory.
Several boxing experts felt the challenger, 31, deserved the victory but the contender endured the second loss of his 28-match professional journey.
The Champion Claims Victory in Dull Encounter
The fighter's advancement has plateaued in recent years through promotional disputes and extended periods of inactivity.
Once tipped as the future of British boxing, he now stands trying to fulfil that early promise - perhaps in what feels like a final roll of the dice - under new promotional backing.
He began cautiously, with both competitors prepared to be aggressive in a tentative early stages.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after suffering a hand injury during the bout, was participating in his second bout at light-heavyweight.
By the halfway stage, Parker had made it competitive, causing problems for Buatsi, who utilized a solid defense to barely take the cleaner periods.
The crowd's patience diminished during frequent holding, with Parker falling to the floor multiple occasions during grappling.
Parker closed well, but multiple periods were difficult to score. However, former world champion the boxing analyst - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just a single round.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the co-main event, Lyndon Arthur overcame Bradley Rea by close verdict in a terrific Manchester vs Manchester fight to secure the European light-heavyweight championship.
The arena fell silent for a deeply poignant homage prior to the bout as a bell ceremony rang in honor of the city's native Hatton, who died 46 years old in September.
It was the first major televised boxing event in the city since the passing of Hatton. As the final chime ended, the silence transitioned to a shout of "only one Ricky Hatton".
The competition inside the ropes matched the emotion. The eventual winner was sent to the canvas by a left hook flush on the chin in the second round, rising shakily to his feet on the count of eight.
But the traditional red equipment of the fighter soon advanced again. Across the ring, the opponent - in rival City blue - was injured soon, significant bruising appearing under his orbital area as the fighters exchanged powerful shots.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity hardly diminished over 12 rounds.
The victor narrowly won the result with official scores of even score, close margin and wider gap, but each competitor were relentless and full of heart, everything their hero Hatton embodied.
