UK light-heavyweight Buatsi earned a win yet unimpressive start to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a competitive ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling clean blows in a match where the techniques never quite clicked, with constant grabbing spoiling the action.
The scoring judges judged it 96-94 to the winner, with the final judge a even score.
"It wasn't my best display but what do champions do? They prevail," the victor stated in the ring as he was faced boos from the audience.
The Londoner bounced back after his maiden career setback - an thrilling contest with his previous opponent in February - to claim a twentieth professional win.
Several boxing experts believed Parker, 31, deserved the win but the contender endured the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Dull Affair
The fighter's advancement has stalled in recent times through promotional disputes and extended periods of inactivity.
Previously predicted as the future of UK boxing, he now is positioned trying to achieve expectations - possibly in what appears to be a last chance - under fresh management.
He opened tentatively, with the two boxers ready to be aggressive in a tentative early stages.
Parker, whose only previous defeat came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was competing in only his second bout at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for Buatsi, who utilized a solid defense to narrowly win the more effective stanzas.
The spectators' acceptance decreased during regular grabbing, with the challenger falling to the floor multiple occasions during clinches.
The underdog finished the stronger, but several stanzas were challenging to assess. Although, former world champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, giving Buatsi just a single round.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Hatton Tribute Inspires All-Manchester Fight
In the supporting bout, Lyndon Arthur overcame Rea by close verdict in a excellent local rivalry battle to win the European light heavyweight championship.
The arena grew hushed for a extremely emotional homage ahead of the contest as ten bells sounded in remembrance of the city's native Hatton, who passed away at age 46 in September.
It was the initial significant broadcast boxing event in the urban center since the passing of Hatton. As the last bell faded, the quiet became a chant of "there's just one Hatton".
The competition during the bout matched the emotion. Arthur was floored by a left hook directly to the jaw in the early round, getting up unsteadily to his footing on the eight count.
But the Manchester United-red attire of the fighter soon advanced again. Across the ring, Rea - in opposing blue - was damaged early, heavy swelling developing under his eye as the pair landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with stinging uppercuts as the action seldom decreased over the full distance.
Arthur edged the decision with official scores of 114-114, narrow lead and wider gap, but the two athletes were persistent and brave, all the qualities their inspiration Hatton represented.
