British light-heavyweight Buatsi secured a victory yet underwhelming start to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a close 10-round bout at the Manchester venue.
But Parker landed significant shots, delivering effective individual punches in a match where the styles didn't complement each other, with frequent clinching disrupting the fight.
Two judges scored it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my greatest performance but what defines champions? They win," Buatsi commented in the ring as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his first professional defeat - an memorable fight with his previous opponent in last winter - to earn a 20th pro success.
Some ringside observers thought the challenger, thirty-one, should have been awarded the win but the contender endured the second loss of his 28-bout professional journey.
The Champion Earns Victory in Dull Affair
The fighter's advancement has plateaued in recent years through promotional disputes and long spells of inactivity.
Once tipped as the future of British boxing, he now finds himself trying to achieve expectations - possibly in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with both competitors ready to be aggressive in a tentative early stages.
The challenger, whose only previous defeat came at super middleweight against John Ryder in 2022 after breaking his hand mid-fight, was participating in his second fight at light heavyweight.
By the middle rounds, Parker had made it competitive, making life awkward for Buatsi, who operated with a tight guard to edge the better stanzas.
The audience's tolerance wore thin during constant clinching, with the challenger going down several times during clinches.
The underdog ended stronger, but several stanzas were hard to judge. Although, former world champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi moves on, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Contest
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a terrific all-Manchester fight to win the European light-heavyweight championship.
The venue grew hushed for a extremely emotional tribute ahead of the contest as 10 bells sounded in memory of the city's native Ricky Hatton, who succumbed at age 46 in last month.
It was the premier televised match card in the urban center since Hatton's death. As the final chime faded, the silence became a roar of "only one Hatton".
The competition within the ring matched the emotion. Arthur was sent to the canvas by a left hook directly to the face in the early round, standing uncertainly to his footing on the count of eight.
But the Manchester United-red attire of the fighter soon advanced again. On the opposite side, Rea - in opposing blue - was marked up soon, significant bruising appearing under his orbital area as the fighters traded hard punches.
The challenger, 27, connected with strong blows but the champion, thirty-four, responded in kind with stinging uppercuts as the action hardly diminished over the full distance.
The victor barely secured the result with judges scorecards of even score, close margin and wider gap, but the two athletes were relentless and courageous, everything their idol Hatton embodied.
