British light heavyweight Buatsi earned a win yet underwhelming beginning to his career under new promoters with a decision win over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a judges' verdict in a close ten-round bout at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful single shots in a match where the techniques failed to mesh, with excessive holding spoiling the action.
The scoring judges judged it 96-94 for to the winner, with the remaining official a 95-95.
"It wasn't my finest display but how do champions respond? They succeed," the victor said in the arena as he was faced disapproval from the spectators.
The British fighter returned to winning ways after his maiden career setback - an epic battle with his previous opponent in last winter - to secure a 20th career victory.
Various analysts believed the challenger, thirty-one, merited the decision but the British boxer suffered the second setback of his 28-match career.
Buatsi Claims Triumph in Dull Match
Buatsi's progress has plateaued in recent times through management issues and extended periods of lack of fights.
Earlier forecast as the future of the British fight scene, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter ready to be aggressive in a tentative opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in 2022 after breaking his hand mid-fight, was competing in only his second bout at the higher weight class.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who operated with a protective stance to narrowly win the better stanzas.
The crowd's patience decreased during frequent holding, with the challenger falling to the floor various instances during close exchanges.
The underdog ended stronger, but several stanzas were difficult to score. However, former world champion the boxing analyst - commentating on the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
The victor moves on, but with the presence of hard hitter Benavidez, and Russian star Bivol leading the category, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Homage Inspires All-Manchester Contest
In the supporting bout, Lyndon Arthur beat Bradley Rea by close verdict in a excellent Manchester vs Manchester battle to win the continental belt.
The stadium fell silent for a deeply poignant tribute prior to the bout as ten bells rang in honor of local hero Hatton, who died aged 46 in last month.
It was the first major televised boxing event in the location since Hatton's passing. As the concluding sound ended, the quiet became a roar of "there's just one Hatton".
The competition during the bout equaled the feeling. The eventual winner was knocked down by a significant blow flush on the face in the early round, standing uncertainly to his footing on the referee's count.
But the traditional red shorts of the fighter soon came forward again. Across the ring, the opponent - in competitive blue - was injured quickly, significant bruising developing under his orbital area as the duo landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, responded in kind with powerful upward punches as the action rarely dropped over the full distance.
The victor edged the result with judges scorecards of even score, close margin and 115-112, but both fighters were persistent and full of heart, all the qualities their inspiration Hatton embodied.
