UK light heavyweight Buatsi earned a win yet disappointing beginning to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a majority decision in a close 10-round bout at the boxing arena.
But the challenger found success, delivering effective individual punches in a contest where the techniques failed to mesh, with constant grabbing marring the contest.
Two judges judged it 96-94 to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest showing but what defines champions? They succeed," Buatsi stated in the ring as he was faced boos from the spectators.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with his previous opponent in last winter - to secure a 20th career victory.
Several boxing experts felt Parker, thirty-one, merited the win but the Derbyshire fighter suffered the second defeat of his 28-bout professional journey.
Buatsi Earns Win in Dull Encounter
The fighter's advancement has plateaued in recent years through promotional disputes and extended periods of lack of fights.
Earlier forecast as the future of UK boxing, he now stands trying to fulfil that early promise - perhaps in what appears to be a last chance - under new promotional backing.
He started carefully, with both competitors willing to take risks in a calculated opening few rounds.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at the higher weight class.
By the middle rounds, the underdog had stayed in contention, making life awkward for Buatsi, who worked behind a solid defense to barely take the cleaner periods.
The spectators' acceptance wore thin because of regular grabbing, with the challenger falling to the floor multiple occasions during close exchanges.
The underdog finished the stronger, but many rounds were hard to judge. Nevertheless, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Hatton Tribute Inspires Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Rea by split-decision in a terrific all-Manchester battle to capture the European light-heavyweight championship.
The venue became quiet for a extremely emotional homage before the fight as 10 bells sounded in honor of the city's native Hatton, who succumbed 46 years old in September.
It was the first major televised match card in the city since the passing of Hatton. As the last bell disappeared, the stillness gave way to a shout of "there's only one Hatton".
The action during the bout equaled the emotion. Arthur was floored by a significant blow squarely on the chin in the early round, rising shakily to his footing on the count of eight.
But the traditional red shorts of Arthur soon came forward again. Across the ring, Rea - in opposing blue - was injured quickly, significant bruising appearing under his face as the fighters landed powerful shots.
The challenger, 27, landed power punches but the champion, thirty-four, matched the intensity with powerful upward punches as the intensity hardly diminished over twelve rounds.
Arthur narrowly won the verdict with judges scorecards of even score, narrow lead and 115-112, but both fighters were relentless and full of heart, all the qualities their inspiration Hatton stood for.
