British light heavyweight Buatsi made a winning yet disappointing start to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a close 10-round bout at the Co-op Live Arena.
But Parker had his moments, landing some telling individual punches in a contest where the approaches didn't complement each other, with constant grabbing disrupting the action.
The officials had it 96-94 for to the winner, with the final judge a even score.
"It wasn't my finest showing but what do champions do? They win," the victor said in the ring as he was greeted with disapproval from the spectators.
The Londoner got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to secure a 20th career victory.
Various analysts felt Parker, 31, deserved the win but the Derbyshire fighter experienced the second loss of his 28-match career.
The Champion Earns Victory in Dull Affair
Buatsi's progress has plateaued in the past few years through management issues and long spells of inactivity.
Once tipped as the future of the British fight scene, he now is positioned trying to realize his potential - perhaps in what seems like a final roll of the dice - under new promotional backing.
He started carefully, with both competitors prepared to take risks in a calculated early stages.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in 2022 after suffering a hand injury in the contest, was competing in only his second bout at light heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who worked behind a protective stance to edge the better periods.
The spectators' acceptance wore thin because of constant clinching, with Parker going down several times during close exchanges.
The underdog ended stronger, but many rounds were difficult to score. Although, previous titleholder Carl Frampton - working with Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
The victor progresses, but with the presence of hard hitter David Benavidez, and Russian star Dmitry Bivol ruling the division, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Homage Fuels Manchester Derby Contest
In the co-main event, Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester contest to capture the European light-heavyweight belt.
The arena grew hushed for a extremely emotional tribute before the fight as a bell ceremony sounded in honor of the city's native Hatton, who died 46 years old in last month.
It was the initial significant broadcast match card in the city since Hatton's passing. As the concluding sound faded, the silence gave way to a roar of "there's just one Hatton".
The competition within the ring reflected the sentiment. The eventual winner was knocked down by a powerful punch squarely on the jaw in the second round, getting up unsteadily to his feet on the referee's count.
But the Manchester United-red attire of Arthur soon advanced again. On the opposite side, Rea - in rival City blue - was marked up soon, significant bruising developing under his orbital area as the duo traded punishing blows.
Rea, 27, delivered effective strikes but the champion, 34, responded in kind with stinging uppercuts as the intensity hardly diminished over twelve rounds.
The victor barely secured the verdict with judges scorecards of 114-114, 115-113 and clearer margin, but each competitor were persistent and full of heart, exactly what their hero Hatton embodied.
