British light-heavyweight Buatsi made a winning yet unimpressive debut to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a close ten-round bout at the Co-op Live Arena.
But the challenger found success, delivering effective clean blows in a match where the styles failed to mesh, with excessive holding spoiling the fight.
The scoring judges judged it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my greatest showing but what do champions do? They prevail," Buatsi said in the arena as he was greeted with boos from the spectators.
The British fighter returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in February - to earn a twentieth professional win.
Several boxing experts felt Parker, 31, should have been awarded the win but the British boxer endured the second loss of his 28-bout career.
The Champion Claims Victory in Dull Encounter
Buatsi's progress has plateaued in recent times through contract problems and long spells of inactivity.
Previously predicted as the future of the British fight scene, he now stands trying to achieve expectations - perhaps in what appears to be a last chance - under new promotional backing.
He began cautiously, with both competitors willing to take risks in a tentative initial rounds.
The challenger, whose only previous defeat came at super middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who utilized a solid defense to barely take the more effective periods.
The audience's tolerance diminished amid constant clinching, with Parker falling to the floor multiple occasions during grappling.
Parker ended stronger, but multiple periods were difficult to score. Nevertheless, previous titleholder the boxing analyst - working with Dazn - had it significantly in favor for the challenger, scoring for Buatsi just one round.
Buatsi advances, but with the likes of hard hitter David Benavidez, and Russian champion Bivol dominating the weight class, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Memorial Inspires Local Rivalry Contest
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a excellent Manchester vs Manchester fight to win the continental championship.
The stadium grew hushed for a profoundly moving homage before the fight as a bell ceremony tolled in remembrance of local hero Hatton, who passed away 46 years old in last month.
It was the premier televised match card in the location since Hatton's death. As the last bell disappeared, the silence transitioned to a roar of "there's only one Ricky Hatton".
The fighting inside the ropes matched the feeling. The eventual winner was floored by a significant blow squarely on the chin in the second round, rising shakily to his feet on the eight count.
But the traditional red shorts of Arthur soon came forward again. Across the ring, the opponent - in opposing blue - was marked up quickly, noticeable damage appearing under his orbital area as the fighters landed hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with stinging uppercuts as the pace rarely dropped over the full distance.
The victor barely secured the result with judges scorecards of even score, narrow lead and wider gap, but both fighters were relentless and brave, everything their inspiration Hatton stood for.
