British light-heavyweight Buatsi earned a win yet disappointing debut to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a close ten-round fight at the Manchester venue.
But the challenger landed significant shots, delivering effective clean blows in a match where the styles never quite clicked, with frequent clinching disrupting the fight.
Two judges judged it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my finest display but what do champions do? They prevail," Buatsi stated in the ring as he was met by disapproval from the audience.
The British fighter bounced back after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, should have been awarded the victory but the British boxer experienced the second loss of his 28-match career.
Buatsi Earns Victory in Uneventful Affair
Buatsi's progress has stalled in recent years through promotional disputes and extended periods of inactivity.
Previously predicted as the future of British boxing, he now stands trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under recent support.
He started carefully, with the two boxers ready to overcommit in a cagey opening few rounds.
Parker, whose single earlier setback came at super middleweight against John Ryder in 2022 after damaging his hand mid-fight, was participating in his second bout at light heavyweight.
By the middle rounds, Parker had stayed in contention, creating difficulties for the favorite, who worked behind a tight guard to barely take the more effective rounds.
The crowd's patience wore thin during frequent holding, with the challenger falling to the floor several times during grappling.
Parker finished the stronger, but many rounds were difficult to score. Although, previous titleholder the boxing analyst - working with Dazn - had it strongly leaning for the challenger, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the caliber of heavy hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Memorial Inspires Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding local rivalry fight to win the European light-heavyweight belt.
The stadium became quiet for a profoundly moving tribute prior to the bout as 10 bells tolled in honor of the city's native Hatton, who passed away 46 years old in last month.
It was the premier televised boxing event in the location since the passing of Hatton. As the last bell ended, the stillness became a roar of "there's just one Hatton".
The action within the ring equaled the feeling. The eventual winner was floored by a powerful punch directly to the jaw in the initial stage, getting up unsteadily to his footing on the referee's count.
But the traditional red shorts of Arthur soon pressed ahead again. On the opposite side, the opponent - in rival City blue - was marked up quickly, significant bruising developing under his orbital area as the duo traded hard punches.
The challenger, twenty-seven, landed power punches but the champion, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over twelve rounds.
Arthur barely secured the verdict with judges scorecards of even score, narrow lead and clearer margin, but the two athletes were persistent and full of heart, exactly what their inspiration Hatton stood for.
