British light-heavyweight Buatsi made a winning yet unimpressive start to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a majority decision in a competitive ten-round contest at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful single shots in a fight where the styles never quite clicked, with frequent clinching marring the action.
The scoring judges judged it 96-94 to the winner, with the third a 95-95.
"It wasn't my greatest performance but what defines champions? They prevail," the victor stated in the ring as he was greeted with disapproval from the crowd.
The British fighter bounced back after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Some ringside observers felt the challenger, 31, merited the victory but the Derbyshire fighter experienced the second defeat of his 28-fight professional journey.
The Champion Secures Victory in Uneventful Encounter
Buatsi's progress has stalled in recent times through management issues and considerable time of inactivity.
Previously predicted as the future of UK boxing, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under fresh management.
He opened tentatively, with the two boxers willing to be aggressive in a cagey opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was making just his second fight at light heavyweight.
By the halfway stage, Parker had kept it close, causing problems for the favorite, who utilized a tight guard to barely take the more effective periods.
The crowd's patience diminished amid frequent holding, with the challenger falling to the floor several times during close exchanges.
The underdog ended stronger, but several stanzas were hard to judge. Although, former world champion Carl Frampton - commentating on Dazn - had it significantly in favor for Parker, scoring for Buatsi just only one stanza.
The victor progresses, but with the presence of heavy hitter David Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - based on this performance - still appears challenging.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the co-main event, Arthur beat Rea by divided decision in a excellent all-Manchester contest to capture the continental title.
The venue fell silent for a deeply poignant homage before the fight as a bell ceremony sounded in remembrance of the city's native Ricky Hatton, who succumbed at age 46 in September.
It was the first major televised boxing event in the urban center since Hatton's death. As the concluding sound disappeared, the silence became a chant of "there's only one Hatton".
The fighting inside the ropes equaled the feeling. The eventual winner was knocked down by a powerful punch squarely on the chin in the early round, rising shakily to his footing on the eight count.
But the red-colored equipment of the fighter soon came forward again. On the opposite side, the opponent - in competitive blue - was marked up early, significant bruising appearing under his face as the pair exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with effective uppercuts as the action hardly diminished over the full distance.
The victor edged the decision with official scores of 114-114, 115-113 and 115-112, but both fighters were determined and brave, everything their inspiration the legend stood for.
