British light heavyweight Buatsi made a winning yet disappointing beginning to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's activity level appeared to earn him a split decision in a close 10-round fight at the Manchester venue.
But Parker landed significant shots, connecting with powerful individual punches in a match where the styles failed to mesh, with constant grabbing marring the fight.
Two judges scored it 96-94 in favor to the winner, with the third a even score.
"It wasn't my best performance but what do champions do? They succeed," Buatsi stated in the arena as he was met by boos from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a 20th pro success.
Some ringside observers felt Parker, thirty-one, should have been awarded the decision but the Derbyshire fighter experienced the second defeat of his 28-fight career.
The Champion Secures Triumph in Slow Match
His career development has stalled in recent years through contract problems and extended periods of lack of fights.
Earlier forecast as the future of British boxing, he now stands trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under fresh management.
He started carefully, with the two boxers ready to overcommit in a tentative early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after suffering a hand injury in the contest, was participating in his second bout at the higher weight class.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who worked behind a tight guard to barely take the more effective stanzas.
The crowd's patience decreased amid constant clinching, with the challenger falling to the floor various instances during clinches.
The underdog closed well, but several stanzas were difficult to score. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, awarding Buatsi just one round.
Buatsi moves on, but with the caliber of power puncher David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still looks steep.
Hatton Tribute Inspires Manchester Derby Fight
In the supporting bout, Arthur overcame Rea by close verdict in a excellent all-Manchester fight to capture the European light heavyweight championship.
The arena grew hushed for a deeply poignant tribute ahead of the contest as ten bells tolled in memory of local hero Ricky Hatton, who died 46 years old in recently.
It was the premier televised match card in the location since the passing of Hatton. As the final chime disappeared, the quiet transitioned to a shout of "there's only one Ricky Hatton".
The competition within the ring equaled the emotion. Arthur was knocked down by a powerful punch flush on the face in the initial stage, standing uncertainly to his feet on the referee's count.
But the Manchester United-red equipment of the fighter soon came forward again. Across the ring, the opponent - in rival City blue - was injured quickly, significant bruising appearing under his orbital area as the duo landed punishing blows.
The challenger, 27, delivered effective strikes but the champion, thirty-four, matched the intensity with effective uppercuts as the intensity rarely dropped over twelve rounds.
The victor barely secured the result with judges scorecards of even score, 115-113 and clearer margin, but the two athletes were persistent and brave, all the qualities their inspiration the legend stood for.
