British light heavyweight Buatsi secured a victory yet disappointing debut to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a judges' verdict in a competitive ten-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful clean blows in a contest where the styles failed to mesh, with excessive holding spoiling the action.
Two judges scored it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my finest performance but how do champions respond? They prevail," the victor stated in the arena as he was met by negative reactions from the spectators.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with his previous opponent in February - to earn a 20th career victory.
Various analysts felt Parker, 31, should have been awarded the win but the British boxer endured the second defeat of his 28-match professional journey.
The Champion Secures Victory in Dull Affair
Buatsi's progress has plateaued in recent times through management issues and long spells of lack of fights.
Once tipped as the future of British boxing, he now is positioned trying to fulfil that early promise - possibly in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers ready to be aggressive in a tentative opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was making just his second appearance at the higher weight class.
By the halfway stage, the underdog had made it competitive, creating difficulties for the favorite, who worked behind a protective stance to edge the better stanzas.
The audience's tolerance decreased during frequent holding, with Parker falling to the floor multiple occasions during close exchanges.
Parker ended stronger, but many rounds were difficult to score. Nevertheless, ex-champion the boxing analyst - commentating on Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the caliber of hard hitter Benavidez, and Russian champion Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Memorial Inspires Manchester Derby Contest
In the co-main event, Lyndon Arthur defeated Rea by split-decision in a excellent local rivalry fight to win the European light-heavyweight championship.
The arena fell silent for a profoundly moving memorial before the fight as ten bells tolled in remembrance of the city's native Ricky Hatton, who died 46 years old in September.
It was the initial significant broadcast match card in the location since Hatton's death. As the concluding sound ended, the quiet became a chant of "there's only one Ricky Hatton".
The action inside the ropes equaled the feeling. The eventual winner was knocked down by a powerful punch directly to the face in the early round, standing uncertainly to his footing on the eight count.
But the Manchester United-red attire of the fighter soon came forward again. From the other corner, the opponent - in competitive blue - was marked up early, significant bruising forming under his orbital area as the duo exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, thirty-four, responded in kind with powerful upward punches as the pace hardly diminished over 12 rounds.
The victor narrowly won the result with judges scorecards of 114-114, narrow lead and wider gap, but both fighters were persistent and brave, exactly what their idol Hatton embodied.
