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 Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a competitive 10-round fight at the Manchester venue.
But Parker landed significant shots, connecting with powerful clean blows in a contest where the techniques didn't complement each other, with excessive holding disrupting the contest.
The officials had it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my finest showing but what defines champions? They prevail," the victor commented in the arena as he was met by disapproval from the spectators.
The British fighter bounced back after his maiden career setback - an thrilling contest with Callum Smith in February - to claim a twentieth professional win.
Several boxing experts thought the challenger, 31, deserved the victory but the contender endured the second setback of his 28-bout career.
The Champion Secures Win in Slow Affair
His career development has stalled in the past few years through promotional disputes and long spells of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter ready to overcommit in a cagey opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in two years ago after breaking his hand mid-fight, was competing in only his second bout at light-heavyweight.
By the middle rounds, the underdog had made it competitive, causing problems for Buatsi, who operated with a solid defense to barely take the cleaner periods.
The audience's tolerance diminished during regular grabbing, with the challenger falling to the floor multiple occasions during close exchanges.
The underdog finished the stronger, but multiple periods were difficult to score. Nevertheless, ex-champion the boxing analyst - commentating on Dazn - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
The victor advances, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Homage Inspires Local Rivalry Contest
In the supporting bout, Lyndon Arthur beat Rea by divided decision in a terrific all-Manchester battle to secure the continental title.
The stadium fell silent for a profoundly moving homage prior to the bout as 10 bells rang in honor of Manchester's own Hatton, who died 46 years old in September.
It was the premier televised match card in the location since Hatton's passing. As the concluding sound faded, the stillness gave way to a chant of "only one Hatton".
The action within the ring reflected the sentiment. The eventual winner was floored by a significant blow directly to the jaw in the second round, standing uncertainly to his position on the eight count.
But the Manchester United-red attire of the fighter soon came forward again. Across the ring, the opponent - in rival City blue - was injured early, heavy swelling appearing under his face as the duo landed punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, matched the intensity with powerful upward punches as the intensity hardly diminished over twelve rounds.
The victor edged the result with official scores of even score, narrow lead and clearer margin, but both fighters were relentless and full of heart, everything their hero Hatton represented.
