British light-heavyweight Buatsi secured a victory yet underwhelming beginning to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a tight 10-round contest at the Co-op Live Arena.
But the challenger found success, delivering effective clean blows in a fight where the approaches didn't complement each other, with constant grabbing marring the action.
The scoring judges judged it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my best display but what defines champions? They succeed," Buatsi commented in the ringside as he was faced boos from the audience.
The British fighter bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a twentieth professional win.
Some ringside observers felt the challenger, 31, should have been awarded the decision but the British boxer suffered the second defeat of his 28-fight career.
Buatsi Earns Win in Dull Affair
His career development has stalled in recent times through management issues and long spells of lack of fights.
Previously predicted as the rising talent of the British fight scene, he now stands trying to fulfil that early promise - possibly in what seems like a ultimate opportunity - under recent support.
He started carefully, with both competitors willing to overcommit in a cagey opening few rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after suffering a hand injury during the bout, was competing in only his second fight at light heavyweight.
By the fight's midpoint, Parker had kept it close, making life awkward for Buatsi, who operated with a protective stance to narrowly win the better periods.
The crowd's patience decreased because of frequent holding, with the challenger falling to the floor various instances during clinches.
Parker closed well, but several stanzas were challenging to assess. Although, former world champion Carl Frampton - working with Dazn - had it significantly in favor for Parker, scoring for Buatsi just one round.
The victor advances, but with the caliber of heavy hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Hatton Tribute Fuels Manchester Derby Battle
In the supporting bout, Arthur beat Bradley Rea by divided decision in a outstanding Manchester vs Manchester fight to capture the European light-heavyweight belt.
The arena fell silent for a profoundly moving tribute prior to the bout as a bell ceremony rang in remembrance of local hero Ricky Hatton, who died at age 46 in recently.
It was the first major televised fight night in the city since Hatton's passing. As the concluding sound faded, the silence gave way to a roar of "there's just one Ricky Hatton".
The fighting inside the ropes equaled the sentiment. Arthur was sent to the canvas by a powerful punch directly to the jaw in the second round, getting up unsteadily to his position on the eight count.
But the traditional red equipment of the fighter soon pressed ahead again. Across the ring, the opponent - in opposing blue - was marked up early, heavy swelling appearing under his face as the pair traded powerful shots.
Rea, 27, delivered effective strikes but the champion, 34, matched the intensity with effective uppercuts as the pace hardly diminished over 12 rounds.
The victor barely secured the result with scoring tallies of 114-114, narrow lead and 115-112, but each competitor were persistent and brave, all the qualities their idol Hatton stood for.
