UK light-heavyweight Buatsi made a winning yet disappointing debut to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a competitive 10-round contest at the Manchester venue.
But Parker had his moments, landing some telling clean blows in a match where the techniques failed to mesh, with excessive holding disrupting the fight.
Two judges judged it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my best display but what do champions do? They succeed," the victor said in the ring as he was greeted with disapproval from the crowd.
The British fighter got back to winning after his initial pro loss - an memorable fight with Callum Smith in February - to earn a 20th pro success.
Various analysts thought Parker, thirty-one, deserved the win but the contender suffered the second defeat of his 28-fight professional journey.
The Champion Secures Victory in Slow Encounter
The fighter's advancement has stalled in the past few years through contract problems and considerable time of inactivity.
Earlier forecast as the future of UK boxing, he now finds himself trying to achieve expectations - maybe in what feels like a last chance - under recent support.
He began cautiously, with neither fighter ready to take risks in a cagey early stages.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was making just his second appearance at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, making life awkward for Buatsi, who operated with a solid defense to narrowly win the more effective rounds.
The audience's tolerance decreased during frequent holding, with Parker going down multiple occasions during close exchanges.
Parker closed well, but multiple periods were hard to judge. Nevertheless, ex-champion the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, giving Buatsi just a single round.
Buatsi moves on, but with the presence of hard hitter David Benavidez, and Russian star Bivol leading the category, the path to championship success - based on this performance - still looks steep.
Hatton Homage Motivates Manchester Derby Battle
In the supporting bout, Arthur overcame Bradley Rea by split-decision in a excellent all-Manchester battle to win the European light-heavyweight title.
The stadium grew hushed for a extremely emotional tribute prior to the bout as a bell ceremony sounded in memory of local hero Ricky Hatton, who died at age 46 in last month.
It was the premier televised boxing event in the urban center since Hatton's passing. As the last bell ended, the silence gave way to a shout of "there's just one Ricky Hatton".
The action within the ring reflected the feeling. The eventual winner was floored by a powerful punch flush on the jaw in the initial stage, standing uncertainly to his footing on the eight count.
But the traditional red attire of Arthur soon came forward again. Across the ring, the opponent - in rival City blue - was marked up quickly, heavy swelling forming under his eye as the pair exchanged powerful shots.
The challenger, twenty-seven, landed power punches but the champion, thirty-four, responded in kind with effective uppercuts as the action seldom decreased over 12 rounds.
The victor edged the verdict with scoring tallies of draw, 115-113 and 115-112, but each competitor were relentless and brave, exactly what their hero the legend represented.
