British light-heavyweight Buatsi secured a victory yet disappointing debut to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a majority decision in a competitive ten-round fight at the Manchester venue.
But the challenger had his moments, connecting with powerful single shots in a contest where the techniques didn't complement each other, with frequent clinching spoiling the action.
The officials had it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my best display but what do champions do? They succeed," Buatsi stated in the ring as he was greeted with disapproval from the audience.
The Londoner got back to winning after his initial pro loss - an epic battle with Callum Smith in last winter - to earn a twentieth professional win.
Various analysts thought the challenger, thirty-one, should have been awarded the win but the contender experienced the second setback of his 28-bout career.
The Champion Earns Victory in Uneventful Encounter
His career development has stalled in the past few years through promotional disputes and long spells of inactivity.
Earlier forecast as the next star of UK boxing, he now is positioned trying to achieve expectations - maybe in what seems like a last chance - under recent support.
He opened tentatively, with both competitors prepared to be aggressive in a calculated opening few rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in 2022 after damaging his hand in the contest, was competing in only his second appearance at light-heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for Buatsi, who worked behind a tight guard to narrowly win the more effective periods.
The audience's tolerance diminished amid regular grabbing, with Parker slipping to the canvas several times during grappling.
Parker closed well, but many rounds were challenging to assess. However, ex-champion Carl Frampton - working with the broadcast network - had it particularly wide for the challenger, giving Buatsi just only one stanza.
The victor progresses, but with the likes of hard hitter David Benavidez, and Russian star Bivol leading the category, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Tribute Motivates Local Rivalry Contest
In the secondary fight, Lyndon Arthur overcame Rea by close verdict in a terrific all-Manchester contest to secure the European light heavyweight belt.
The venue became quiet for a deeply poignant memorial ahead of the contest as a bell ceremony sounded in memory of Manchester's own Ricky Hatton, who passed away 46 years old in September.
It was the initial significant broadcast fight night in the city since Hatton's death. As the last bell disappeared, the quiet gave way to a shout of "there's just one Ricky Hatton".
The fighting during the bout equaled the emotion. Arthur was sent to the canvas by a left hook directly to the chin in the initial stage, standing uncertainly to his feet on the referee's count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. On the opposite side, Rea - in rival City blue - was marked up quickly, significant bruising developing under his face as the duo exchanged powerful shots.
The challenger, 27, connected with strong blows but Arthur, 34, matched the intensity with stinging uppercuts as the pace rarely dropped over 12 rounds.
The victor edged the verdict with scoring tallies of 114-114, narrow lead and clearer margin, but each competitor were determined and full of heart, everything their hero the legend stood for.
