British light heavyweight Buatsi made a winning yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a judges' verdict in a competitive 10-round bout at the boxing arena.
But the challenger landed significant shots, landing some telling single shots in a contest where the styles never quite clicked, with excessive holding marring the contest.
The scoring judges had it 96-94 in favor to Buatsi, with the third a even score.
"It wasn't my finest showing but what defines champions? They prevail," the victor commented in the arena as he was greeted with disapproval from the audience.
The Londoner got back to winning after his first professional defeat - an memorable fight with Callum Smith in last winter - to claim a 20th career victory.
Various analysts felt the challenger, 31, deserved the win but the British boxer endured the second setback of his 28-match professional journey.
Buatsi Earns Triumph in Dull Encounter
The fighter's advancement has stalled in recent times through promotional disputes and considerable time of lack of fights.
Earlier forecast as the next star of British boxing, he now stands trying to achieve expectations - perhaps in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with both competitors prepared to take risks in a tentative initial rounds.
The challenger, whose single earlier setback came at super middleweight against his former opponent in 2022 after breaking his hand during the bout, was making just his second bout at the higher weight class.
By the halfway stage, the underdog had made it competitive, making life awkward for the favorite, who worked behind a solid defense to narrowly win the better periods.
The spectators' acceptance wore thin during constant clinching, with the challenger falling to the floor multiple occasions during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. Although, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for Parker, awarding Buatsi just a single round.
The victor moves on, but with the likes of hard hitter David Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - based on this performance - still looks steep.
Hatton Tribute Motivates Manchester Derby Battle
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding Manchester vs Manchester fight to win the European light-heavyweight belt.
The venue fell silent for a profoundly moving memorial prior to the bout as a bell ceremony tolled in memory of Manchester's own Hatton, who succumbed aged 46 in September.
It was the premier televised fight night in the location since the passing of Hatton. As the last bell faded, the silence became a roar of "there's only one Hatton".
The action during the bout reflected the sentiment. Arthur was knocked down by a powerful punch flush on the chin in the early round, getting up unsteadily to his position on the count of eight.
But the Manchester United-red attire of the fighter soon came forward again. Across the ring, the opponent - in rival City blue - was damaged soon, noticeable damage forming under his eye as the duo exchanged punishing blows.
The challenger, twenty-seven, landed power punches but the champion, 34, fought fire with fire with stinging uppercuts as the pace hardly diminished over 12 rounds.
The victor narrowly won the decision with scoring tallies of even score, narrow lead and wider gap, but both fighters were persistent and full of heart, all the qualities their idol Hatton stood for.
