British light-heavyweight Buatsi earned a win yet underwhelming start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a competitive ten-round bout at the Co-op Live Arena.
But Parker had his moments, landing some telling individual punches in a match where the approaches failed to mesh, with excessive holding disrupting the contest.
The officials had it 96-94 to the winner, with the final judge a even score.
"It wasn't my finest display but what do champions do? They prevail," the victor said in the ring as he was faced boos from the audience.
The Londoner bounced back after his maiden career setback - an memorable fight with his previous opponent in February - to secure a 20th career victory.
Various analysts thought Parker, thirty-one, deserved the decision but the British boxer experienced the second defeat of his 28-match career.
The Champion Claims Win in Dull Match
The fighter's advancement has plateaued in the past few years through management issues and considerable time of inactivity.
Once tipped as the rising talent of British boxing, he now is positioned trying to achieve expectations - possibly in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter prepared to overcommit in a tentative initial rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after damaging his hand mid-fight, was competing in only his second appearance at light-heavyweight.
By the middle rounds, the underdog had kept it close, creating difficulties for Buatsi, who utilized a protective stance to narrowly win the better rounds.
The audience's tolerance wore thin because of regular grabbing, with Parker slipping to the canvas multiple occasions during close exchanges.
The underdog ended stronger, but many rounds were challenging to assess. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just one round.
The victor moves on, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Homage Fuels All-Manchester Battle
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a excellent all-Manchester fight to secure the European light-heavyweight belt.
The stadium grew hushed for a deeply poignant tribute before the fight as a bell ceremony tolled in memory of local hero Hatton, who died at age 46 in September.
It was the initial significant broadcast match card in the location since the passing of Hatton. As the last bell ended, the quiet became a roar of "there's just one Ricky Hatton".
The action during the bout matched the emotion. Arthur was sent to the canvas by a significant blow flush on the jaw in the initial stage, standing uncertainly to his feet on the count of eight.
But the red-colored equipment of the fighter soon pressed ahead again. Across the ring, Rea - in competitive blue - was damaged soon, heavy swelling developing under his face as the pair exchanged powerful shots.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with stinging uppercuts as the action hardly diminished over the full distance.
Arthur barely secured the decision with official scores of even score, close margin and wider gap, but each competitor were relentless and courageous, all the qualities their idol the legend embodied.
