British light-heavyweight Buatsi made a winning yet unimpressive start to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a judges' verdict in a competitive ten-round bout at the Manchester venue.
But Parker had his moments, connecting with powerful single shots in a match where the techniques never quite clicked, with frequent clinching spoiling the action.
The scoring judges judged it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest showing but what defines champions? They prevail," Buatsi stated in the ringside as he was met by negative reactions from the crowd.
The Londoner got back to winning after his initial pro loss - an epic battle with Callum Smith in last winter - to secure a 20th career victory.
Some ringside observers felt Parker, 31, deserved the win but the Derbyshire fighter endured the second setback of his 28-match professional journey.
The Champion Earns Triumph in Uneventful Affair
His career development has stalled in recent times through management issues and considerable time of inactivity.
Previously predicted as the rising talent of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under fresh management.
He started carefully, with the two boxers ready to take risks in a tentative early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in 2022 after suffering a hand injury mid-fight, was participating in his second fight at light heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for Buatsi, who worked behind a tight guard to edge the better stanzas.
The crowd's patience wore thin amid regular grabbing, with the challenger slipping to the canvas several times during grappling.
Parker ended stronger, but multiple periods were hard to judge. However, ex-champion the boxing analyst - providing analysis for Dazn - had it strongly leaning for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Russian star Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Tribute Fuels All-Manchester Battle
In the supporting bout, Lyndon Arthur overcame Bradley Rea by close verdict in a terrific all-Manchester fight to secure the European light heavyweight title.
The stadium fell silent for a extremely emotional tribute before the fight as 10 bells tolled in memory of Manchester's own Hatton, who died at age 46 in last month.
It was the premier televised boxing event in the location since the passing of Hatton. As the final chime faded, the quiet transitioned to a chant of "there's just one Ricky Hatton".
The action within the ring reflected the sentiment. Arthur was floored by a left hook squarely on the chin in the second round, standing uncertainly to his position on the referee's count.
But the traditional red shorts of the fighter soon advanced again. From the other corner, Rea - in rival City blue - was marked up soon, significant bruising developing under his eye as the pair exchanged punishing blows.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with powerful upward punches as the intensity seldom decreased over the full distance.
The victor barely secured the verdict with judges scorecards of draw, close margin and 115-112, but each competitor were relentless and brave, all the qualities their hero Hatton stood for.
