British light-heavyweight Buatsi made a winning yet disappointing beginning to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output likely gained him a judges' verdict in a close ten-round contest at the Manchester venue.
But the challenger had his moments, landing some telling single shots in a fight where the techniques failed to mesh, with excessive holding marring the action.
Two judges judged it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest performance but what defines champions? They prevail," Buatsi stated in the ring as he was met by boos from the audience.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Some ringside observers felt the challenger, 31, merited the victory but the Derbyshire fighter experienced the second setback of his 28-match career.
Buatsi Claims Triumph in Uneventful Encounter
The fighter's advancement has slowed in recent years through management issues and considerable time of lack of fights.
Once tipped as the next star of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what feels like a last chance - under recent support.
He began cautiously, with the two boxers willing to be aggressive in a tentative early stages.
Parker, whose single earlier setback came at super middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was participating in his second fight at light heavyweight.
By the middle rounds, the underdog had stayed in contention, making life awkward for Buatsi, who operated with a protective stance to edge the more effective stanzas.
The crowd's patience decreased amid frequent holding, with Parker going down several times during grappling.
Parker ended stronger, but many rounds were difficult to score. Nevertheless, previous titleholder Carl Frampton - commentating on Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi advances, but with the likes of power puncher David Benavidez, and Russian star Dmitry Bivol leading the category, the journey to titles - based on this performance - still appears challenging.
Hatton Homage Inspires All-Manchester Battle
In the supporting bout, Lyndon Arthur beat Rea by split-decision in a outstanding Manchester vs Manchester contest to capture the continental belt.
The venue grew hushed for a extremely emotional memorial ahead of the contest as 10 bells sounded in honor of the city's native Hatton, who passed away at age 46 in recently.
It was the first major televised match card in the urban center since the passing of Hatton. As the final chime ended, the silence transitioned to a roar of "there's only one Hatton".
The fighting during the bout matched the emotion. Arthur was floored by a significant blow squarely on the chin in the early round, rising shakily to his footing on the referee's count.
But the Manchester United-red equipment of the fighter soon advanced again. From the other corner, Rea - in rival City blue - was marked up soon, significant bruising developing under his face as the pair traded hard punches.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with powerful upward punches as the action seldom decreased over 12 rounds.
Arthur narrowly won the result with official scores of 114-114, 115-113 and wider gap, but the two athletes were persistent and brave, exactly what their idol Hatton stood for.
