UK light-heavyweight Buatsi earned a win yet unimpressive debut to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a majority decision in a tight 10-round bout at the Manchester venue.
But the challenger found success, connecting with powerful individual punches in a fight where the techniques failed to mesh, with constant grabbing disrupting the action.
Two judges judged it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my best performance but what defines champions? They succeed," the victor said in the arena as he was met by disapproval from the spectators.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to earn a twentieth professional win.
Various analysts felt the challenger, thirty-one, merited the decision but the contender experienced the second setback of his 28-bout professional journey.
The Champion Secures Win in Dull Match
Buatsi's progress has slowed in recent years through promotional disputes and long spells of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter ready to take risks in a cagey opening few rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who worked behind a solid defense to barely take the better periods.
The crowd's patience decreased because of constant clinching, with Parker falling to the floor multiple occasions during grappling.
The underdog finished the stronger, but multiple periods were difficult to score. Nevertheless, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Ricky Hatton Homage Inspires Local Rivalry Contest
In the supporting bout, Lyndon Arthur defeated Bradley Rea by close verdict in a excellent local rivalry contest to win the European light heavyweight belt.
The stadium became quiet for a profoundly moving homage prior to the bout as 10 bells sounded in remembrance of Manchester's own Hatton, who succumbed at age 46 in recently.
It was the premier televised match card in the location since the passing of Hatton. As the concluding sound disappeared, the stillness gave way to a roar of "there's only one Hatton".
The fighting inside the ropes reflected the sentiment. The eventual winner was knocked down by a significant blow directly to the chin in the second round, standing uncertainly to his footing on the count of eight.
But the Manchester United-red attire of Arthur soon came forward again. On the opposite side, the opponent - in competitive blue - was injured soon, significant bruising forming under his face as the duo landed powerful shots.
The challenger, 27, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the action seldom decreased over the full distance.
The victor barely secured the decision with scoring tallies of even score, 115-113 and clearer margin, but the two athletes were relentless and courageous, all the qualities their hero the legend stood for.
