British light-heavyweight Buatsi secured a victory yet disappointing start to life under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive 10-round fight at the Manchester venue.
But the challenger found success, delivering effective single shots in a contest where the techniques didn't complement each other, with frequent clinching spoiling the action.
Two judges had it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but what do champions do? They succeed," Buatsi said in the ring as he was met by negative reactions from the spectators.
The Londoner bounced back after his maiden career setback - an memorable fight with Callum Smith in last winter - to secure a 20th career victory.
Some ringside observers thought Parker, thirty-one, merited the victory but the Derbyshire fighter endured the second defeat of his 28-fight professional journey.
Buatsi Claims Victory in Uneventful Match
Buatsi's progress has slowed in recent years through contract problems and extended periods of lack of fights.
Earlier forecast as the future of British boxing, he now is positioned trying to realize his potential - possibly in what feels like a ultimate opportunity - under new promotional backing.
He started carefully, with the two boxers ready to take risks in a cagey initial rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after breaking his hand during the bout, was making just his second bout at light-heavyweight.
By the halfway stage, the underdog had kept it close, making life awkward for the favorite, who utilized a protective stance to barely take the better periods.
The crowd's patience wore thin amid frequent holding, with Parker going down multiple occasions during grappling.
The underdog finished the stronger, but many rounds were difficult to score. However, previous titleholder the boxing analyst - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the likes of hard hitter David Benavidez, and Russian champion Dmitry Bivol leading the category, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Homage Inspires All-Manchester Contest
In the secondary fight, Arthur overcame Bradley Rea by split-decision in a excellent local rivalry battle to win the continental belt.
The arena fell silent for a profoundly moving tribute prior to the bout as 10 bells rang in honor of local hero Hatton, who succumbed at age 46 in last month.
It was the initial significant broadcast boxing event in the city since the passing of Hatton. As the concluding sound faded, the silence became a chant of "there's only one Hatton".
The action within the ring reflected the emotion. Arthur was sent to the canvas by a powerful punch directly to the face in the early round, rising shakily to his feet on the referee's count.
But the traditional red attire of the fighter soon came forward again. Across the ring, the opponent - in opposing blue - was damaged quickly, heavy swelling forming under his face as the duo traded hard punches.
Rea, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the action rarely dropped over twelve rounds.
Arthur edged the decision with scoring tallies of 114-114, close margin and 115-112, but each competitor were persistent and courageous, everything their hero Hatton stood for.
