British light heavyweight Buatsi made a winning yet underwhelming start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a split decision in a tight ten-round fight at the boxing arena.
But the challenger found success, connecting with powerful single shots in a contest where the styles didn't complement each other, with excessive holding disrupting the fight.
The scoring judges scored it 96-94 to the winner, with the final judge a even score.
"It wasn't my greatest display but what do champions do? They succeed," Buatsi stated in the ringside as he was faced boos from the crowd.
The Londoner bounced back after his maiden career setback - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts believed the challenger, 31, should have been awarded the win but the contender endured the second loss of his 28-bout career.
The Champion Secures Victory in Slow Encounter
Buatsi's progress has slowed in the past few years through promotional disputes and considerable time of lack of fights.
Once tipped as the rising talent of UK boxing, he now finds himself trying to fulfil that early promise - maybe in what feels like a last chance - under fresh management.
He opened tentatively, with the two boxers prepared to be aggressive in a cagey initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who utilized a protective stance to edge the more effective periods.
The audience's tolerance decreased because of regular grabbing, with Parker falling to the floor multiple occasions during clinches.
Parker finished the stronger, but many rounds were hard to judge. Although, previous titleholder Carl Frampton - commentating on Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
The victor moves on, but with the likes of heavy hitter Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - on this evidence - still appears challenging.
Hatton Tribute Fuels Manchester Derby Battle
In the supporting bout, Lyndon Arthur defeated Rea by split-decision in a outstanding all-Manchester battle to capture the European light heavyweight title.
The stadium became quiet for a deeply poignant memorial prior to the bout as 10 bells tolled in honor of the city's native Hatton, who died 46 years old in recently.
It was the first major televised fight night in the city since Hatton's death. As the last bell disappeared, the quiet became a roar of "there's just one Hatton".
The action within the ring equaled the sentiment. Arthur was sent to the canvas by a powerful punch flush on the chin in the second round, standing uncertainly to his footing on the eight count.
But the traditional red shorts of Arthur soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was damaged quickly, heavy swelling developing under his eye as the duo exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, responded in kind with powerful upward punches as the pace rarely dropped over the full distance.
Arthur barely secured the decision with judges scorecards of 114-114, narrow lead and clearer margin, but the two athletes were persistent and courageous, exactly what their inspiration Hatton represented.
