UK light heavyweight Buatsi secured a victory yet unimpressive debut to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a majority decision in a competitive ten-round bout at the Manchester venue.
But the challenger landed significant shots, landing some telling individual punches in a fight where the techniques didn't complement each other, with constant grabbing disrupting the fight.
The scoring judges judged it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my best display but how do champions respond? They prevail," Buatsi commented in the ringside as he was met by disapproval from the audience.
The British fighter bounced back after his first professional defeat - an epic battle with his previous opponent in February - to secure a twentieth professional win.
Various analysts believed the challenger, 31, deserved the decision but the contender experienced the second setback of his 28-fight career.
The Champion Claims Win in Slow Match
Buatsi's progress has plateaued in recent times through management issues and long spells of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a cagey early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after suffering a hand injury during the bout, was participating in his second bout at light heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who worked behind a solid defense to narrowly win the cleaner stanzas.
The spectators' acceptance wore thin amid regular grabbing, with Parker falling to the floor various instances during close exchanges.
The underdog ended stronger, but several stanzas were difficult to score. Although, former world champion 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 likes of heavy hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - judging by this showing - still seems difficult.
Ricky Hatton Tribute Inspires Manchester Derby Contest
In the secondary fight, Lyndon Arthur overcame Rea by split-decision in a excellent Manchester vs Manchester battle to win the European light-heavyweight championship.
The stadium became quiet for a deeply poignant homage ahead of the contest as ten bells sounded in remembrance of the city's native Ricky Hatton, who died aged 46 in September.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound disappeared, the stillness transitioned to a chant of "only one Hatton".
The fighting inside the ropes matched the emotion. Arthur was knocked down by a left hook directly to the chin in the initial stage, standing uncertainly to his footing on the count of eight.
But the Manchester United-red attire of Arthur soon advanced again. From the other corner, the opponent - in rival City blue - was injured quickly, significant bruising appearing under his eye as the pair landed powerful shots.
The challenger, 27, landed power punches but the champion, thirty-four, matched the intensity with effective uppercuts as the pace rarely dropped over twelve rounds.
Arthur edged the decision with official scores of even score, close margin and clearer margin, but both fighters were persistent and full of heart, exactly what their inspiration the legend embodied.
