British light-heavyweight Buatsi secured a victory yet disappointing start to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a judges' verdict in a tight ten-round fight at the Co-op Live Arena.
But Parker had his moments, landing some telling single shots in a fight where the styles didn't complement each other, with constant grabbing marring the contest.
The officials had it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best performance but how do champions respond? They succeed," Buatsi stated in the ring as he was greeted with disapproval from the spectators.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with Callum Smith in last winter - to secure a 20th pro success.
Some ringside observers thought Parker, 31, merited the decision but the Derbyshire fighter experienced the second defeat of his 28-fight career.
The Champion Claims Win in Uneventful Encounter
Buatsi's progress has stalled in recent times through management issues and long spells of lack of fights.
Once tipped as the next star of the British fight scene, he now stands trying to realize his potential - perhaps in what feels like a last chance - under new promotional backing.
He opened tentatively, with the two boxers willing to take risks in a cagey initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand mid-fight, was participating in his second bout at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for the favorite, who worked behind a tight guard to edge the cleaner periods.
The crowd's patience decreased amid constant clinching, with the challenger slipping to the canvas multiple occasions during close exchanges.
Parker finished the stronger, but many rounds were difficult to score. Although, ex-champion Carl Frampton - commentating on the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi advances, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Hatton Memorial Motivates All-Manchester Battle
In the co-main event, Lyndon Arthur beat Rea by split-decision in a terrific local rivalry fight to win the continental championship.
The stadium fell silent for a deeply poignant memorial prior to the bout as 10 bells tolled in honor of the city's native Hatton, who passed away 46 years old in September.
It was the first major televised match card in the urban center since Hatton's passing. As the last bell ended, the silence transitioned to a shout of "there's just one Hatton".
The competition within the ring matched the sentiment. The eventual winner was sent to the canvas by a significant blow directly to the chin in the initial stage, rising shakily to his position on the eight count.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, the opponent - in competitive blue - was marked up quickly, noticeable damage forming under his face as the pair exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, 34, responded in kind with powerful upward punches as the intensity rarely dropped over the full distance.
The victor barely secured the result with official scores of even score, 115-113 and clearer margin, but the two athletes were persistent and courageous, all the qualities their inspiration Hatton embodied.
