UK light heavyweight Buatsi secured a victory yet underwhelming debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a tight ten-round fight at the Manchester venue.
But Parker had his moments, connecting with powerful individual punches in a contest where the techniques didn't complement each other, with excessive holding spoiling the action.
The officials had it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi stated in the ringside as he was faced negative reactions from the spectators.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to secure a 20th career victory.
Several boxing experts believed the challenger, thirty-one, merited the decision but the British boxer suffered the second defeat of his 28-match professional journey.
Buatsi Earns Win in Dull Affair
His career development has plateaued in the past few years through management issues and long spells of inactivity.
Earlier forecast as the future of British boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter ready to take risks in a calculated opening few rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second fight at light-heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who operated with a solid defense to barely take the more effective rounds.
The spectators' acceptance wore thin because of constant clinching, with the challenger slipping to the canvas various instances during grappling.
The underdog closed well, but several stanzas were hard to judge. However, previous titleholder Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just a single round.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Memorial Fuels Manchester Derby Contest
In the co-main event, Lyndon Arthur defeated Bradley Rea by divided decision in a outstanding Manchester vs Manchester contest to secure the European light-heavyweight belt.
The venue fell silent for a extremely emotional memorial ahead of the contest as a bell ceremony sounded in remembrance of Manchester's own Hatton, who died aged 46 in last month.
It was the premier televised match card in the urban center since Hatton's death. As the final chime ended, the quiet gave way to a shout of "there's just one Ricky Hatton".
The competition during the bout reflected the feeling. Arthur was sent to the canvas by a left hook flush on the chin in the initial stage, getting up unsteadily to his footing on the eight count.
But the traditional red equipment of Arthur soon pressed ahead again. Across the ring, Rea - in competitive blue - was damaged quickly, heavy swelling appearing under his face as the pair traded hard punches.
Rea, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with effective uppercuts as the pace rarely dropped over the full distance.
Arthur edged the result with judges scorecards of draw, close margin and clearer margin, but both fighters were persistent and courageous, exactly what their inspiration Hatton embodied.
