UK light-heavyweight Buatsi made a winning yet disappointing debut 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 tight 10-round bout at the Co-op Live Arena.
But Parker found success, connecting with powerful individual punches in a fight where the styles never quite clicked, with frequent clinching spoiling the contest.
The officials judged it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my greatest performance but what do champions do? They succeed," Buatsi commented in the arena as he was met by boos from the spectators.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in February - to earn a 20th pro success.
Several boxing experts believed the challenger, thirty-one, should have been awarded the win but the Derbyshire fighter suffered the second setback of his 28-match career.
The Champion Earns Win in Slow Encounter
Buatsi's progress has stalled in the past few years through promotional disputes and extended periods of inactivity.
Previously predicted as the next star of UK boxing, he now is positioned trying to achieve expectations - perhaps in what feels like a last chance - under recent support.
He began cautiously, with neither fighter ready to take risks in a cagey early stages.
Parker, whose only previous defeat came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was competing in only his second fight at the higher weight class.
By the middle rounds, Parker had stayed in contention, creating difficulties for the favorite, who utilized a protective stance to narrowly win the more effective rounds.
The crowd's patience diminished during frequent holding, with the challenger falling to the floor several times during grappling.
Parker closed well, but multiple periods were difficult to score. Although, ex-champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, awarding Buatsi just a single round.
The victor progresses, but with the caliber of hard hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Hatton Tribute Inspires Local Rivalry Battle
In the co-main event, Lyndon Arthur beat Rea by divided decision in a outstanding local rivalry battle to secure the European light heavyweight belt.
The arena fell silent for a deeply poignant homage ahead of the contest as ten bells sounded in memory of Manchester's own Hatton, who passed away aged 46 in September.
It was the initial significant broadcast boxing event in the urban center since the passing of Hatton. As the last bell ended, the quiet became a chant of "there's just one Ricky Hatton".
The fighting during the bout reflected the sentiment. The eventual winner was floored by a powerful punch squarely on the face in the early round, rising shakily to his footing on the referee's count.
But the Manchester United-red equipment of the fighter soon came forward again. Across the ring, Rea - in competitive blue - was injured quickly, noticeable damage developing under his face as the duo traded punishing blows.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity seldom decreased over twelve rounds.
Arthur narrowly won the verdict with judges scorecards of draw, narrow lead and clearer margin, but the two athletes were relentless and brave, everything their idol Hatton stood for.
