British light heavyweight Buatsi made a winning yet unimpressive debut to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a split decision in a competitive ten-round fight at the boxing arena.
But the challenger found success, delivering effective clean blows in a match where the techniques never quite clicked, with constant grabbing spoiling the action.
The scoring judges had it 96-94 to the winner, with the final judge a 95-95.
"It wasn't my finest showing but what do champions do? They win," the victor commented in the arena as he was greeted with disapproval from the audience.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in February - to earn a 20th pro success.
Some ringside observers felt the challenger, 31, merited the decision but the contender suffered the second defeat of his 28-bout professional journey.
Buatsi Earns Triumph in Slow Affair
The fighter's advancement has slowed in the past few years through management issues and extended periods of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to realize his potential - perhaps in what seems like a last chance - under fresh management.
He started carefully, with both competitors willing to overcommit in a tentative initial rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in 2022 after damaging his hand in the contest, was competing in only his second appearance at light-heavyweight.
By the middle rounds, the underdog had kept it close, making life awkward for Buatsi, who operated with a protective stance to narrowly win the more effective rounds.
The spectators' acceptance diminished during constant clinching, with Parker slipping to the canvas various instances during grappling.
Parker ended stronger, but many rounds were difficult to score. However, previous titleholder the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just only one stanza.
The victor progresses, but with the presence of heavy hitter David Benavidez, and Russian star Bivol leading the category, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Homage Inspires All-Manchester Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by divided decision in a outstanding local rivalry fight to secure the continental belt.
The venue grew hushed for a deeply poignant tribute ahead of the contest as ten bells tolled in memory of the city's native Hatton, who died aged 46 in last month.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the concluding sound ended, the quiet gave way to a roar of "there's just one Hatton".
The competition within the ring matched the emotion. Arthur was sent to the canvas by a powerful punch squarely on the jaw in the second round, standing uncertainly to his feet on the count of eight.
But the Manchester United-red attire of Arthur soon came forward again. Across the ring, the opponent - in competitive blue - was injured quickly, significant bruising appearing under his orbital area as the fighters exchanged punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the intensity hardly diminished over the full distance.
Arthur barely secured the result with official scores of 114-114, narrow lead and wider gap, but the two athletes were determined and full of heart, everything their inspiration Hatton embodied.
