British light heavyweight Buatsi made a winning yet underwhelming beginning 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 split decision in a competitive ten-round contest at the Co-op Live Arena.
But the challenger had his moments, landing some telling individual punches in a match where the techniques never quite clicked, with frequent clinching marring the fight.
Two judges scored it 96-94 for to the winner, with the third a 95-95.
"It wasn't my best performance but how do champions respond? They win," the victor commented in the ringside as he was greeted with boos from the crowd.
The Londoner got back to winning after his first professional defeat - an epic battle with Callum Smith in February - to earn a twentieth professional win.
Some ringside observers believed Parker, thirty-one, merited the win but the Derbyshire fighter experienced the second loss of his 28-match career.
The Champion Earns Win in Uneventful Match
The fighter's advancement has plateaued in recent times through contract problems and long spells of inactivity.
Earlier forecast as the future of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what feels like a ultimate opportunity - under new promotional backing.
He started carefully, with both competitors willing to be aggressive in a tentative early stages.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after breaking his hand during the bout, was participating in his second appearance at light-heavyweight.
By the fight's midpoint, Parker had kept it close, making life awkward for the favorite, who worked behind a protective stance to edge the better periods.
The audience's tolerance decreased during constant clinching, with Parker slipping to the canvas several times during close exchanges.
Parker finished the stronger, but many rounds were difficult to score. Although, former world champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Fight
In the supporting bout, Arthur defeated Rea by divided decision in a terrific local rivalry fight to secure the continental title.
The venue grew hushed for a profoundly moving homage before the fight as a bell ceremony tolled in memory of Manchester's own Hatton, who died aged 46 in recently.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound ended, the quiet became a roar of "there's only one Hatton".
The competition inside the ropes equaled the feeling. Arthur was knocked down by a powerful punch squarely on the face in the initial stage, getting up unsteadily to his footing on the count of eight.
But the traditional red equipment of Arthur soon came forward again. On the opposite side, Rea - in rival City blue - was marked up quickly, significant bruising appearing under his orbital area as the fighters traded powerful shots.
The challenger, 27, landed power punches but Arthur, thirty-four, responded in kind with powerful upward punches as the action seldom decreased over twelve rounds.
The victor barely secured the verdict with judges scorecards of even score, close margin and wider gap, but the two athletes were determined and brave, everything their idol Hatton stood for.
