UK light-heavyweight Buatsi earned a win yet underwhelming debut to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a split decision in a close ten-round bout at the Manchester venue.
But the challenger found success, delivering effective individual punches in a match where the techniques never quite clicked, with excessive holding spoiling the fight.
The scoring judges scored it 96-94 in favor to Buatsi, with the third 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 faced disapproval from the crowd.
The British fighter bounced back after his initial pro loss - an epic battle with Callum Smith in February - to earn a 20th pro success.
Various analysts felt Parker, thirty-one, merited the victory but the contender endured the second setback of his 28-bout professional journey.
The Champion Earns Win in Slow Match
His career development has slowed in recent times through contract problems and extended periods of lack of fights.
Previously predicted as the next star of the British fight scene, he now is positioned trying to achieve expectations - perhaps in what seems like a final roll of the dice - under fresh management.
He opened tentatively, with neither fighter ready to overcommit in a cagey initial rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in 2022 after breaking his hand in the contest, was participating in his second appearance at light heavyweight.
By the middle rounds, Parker had made it competitive, creating difficulties for Buatsi, who worked behind a solid defense to barely take the more effective stanzas.
The spectators' acceptance diminished during regular grabbing, with Parker slipping to the canvas various instances during grappling.
The underdog ended stronger, but many rounds were difficult to score. However, ex-champion Carl Frampton - commentating on the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
The victor moves on, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - judging by this showing - still looks steep.
Hatton Tribute Motivates Manchester Derby Fight
In the supporting bout, Lyndon Arthur overcame Bradley Rea by divided decision in a excellent all-Manchester contest to capture the European light heavyweight title.
The venue became quiet for a deeply poignant memorial before the fight as ten bells rang in memory of local hero Ricky Hatton, who died at age 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's death. As the last bell faded, the quiet transitioned to a roar of "only one Hatton".
The competition within the ring matched the feeling. The eventual winner was knocked down by a significant blow directly to the jaw in the initial stage, getting up unsteadily to his feet on the eight count.
But the traditional red shorts of the fighter soon came forward again. From the other corner, the opponent - in competitive blue - was injured early, significant bruising appearing under his face as the duo exchanged hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, responded in kind with powerful upward punches as the intensity seldom decreased over twelve rounds.
Arthur barely secured the result with official scores of 114-114, close margin and 115-112, but the two athletes were determined and brave, everything their inspiration the legend stood for.
