British light heavyweight Buatsi made a winning yet disappointing start to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive ten-round bout at the boxing arena.
But Parker had his moments, delivering effective individual punches in a fight where the techniques didn't complement each other, with constant grabbing disrupting the contest.
The scoring judges judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my best performance but how do champions respond? They win," the victor stated in the ringside as he was met by negative reactions from the spectators.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Various analysts felt Parker, thirty-one, deserved the decision but the Derbyshire fighter endured the second defeat of his 28-fight career.
Buatsi Secures Triumph in Uneventful Encounter
Buatsi's progress has plateaued in recent times through contract problems and extended periods of lack of fights.
Earlier forecast as the rising talent of UK boxing, he now stands trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with the two boxers prepared to take risks in a cagey opening few rounds.
Parker, whose only previous defeat came at super middleweight against John Ryder in 2022 after damaging his hand during the bout, was participating in his second fight at the higher weight class.
By the middle rounds, the underdog had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to edge the better periods.
The audience's tolerance diminished during regular grabbing, with the challenger slipping to the canvas several times during close exchanges.
Parker ended stronger, but many rounds were difficult to score. Although, former world champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, giving Buatsi just only one stanza.
The victor moves on, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Memorial Fuels Local Rivalry Contest
In the supporting bout, Arthur overcame Bradley Rea by close verdict in a terrific local rivalry fight to capture the European light-heavyweight belt.
The venue fell silent for a profoundly moving memorial before the fight as 10 bells sounded in remembrance of Manchester's own Ricky Hatton, who succumbed 46 years old in recently.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the stillness transitioned to a shout of "only one Hatton".
The fighting during the bout matched the feeling. Arthur was knocked down by a left hook directly to the chin in the early round, rising shakily to his feet on the count of eight.
But the traditional red equipment of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was marked up soon, significant bruising appearing under his eye as the pair traded powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with powerful upward punches as the intensity hardly diminished over the full distance.
The victor edged the verdict with scoring tallies of draw, close margin and 115-112, but both fighters were determined and courageous, everything their inspiration Hatton stood for.
