British light-heavyweight Buatsi earned a win yet disappointing start to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a close ten-round bout at the boxing arena.
But Parker found success, landing some telling individual punches in a contest where the techniques didn't complement each other, with frequent clinching spoiling the contest.
The officials judged it 96-94 to Buatsi, with the remaining official a even score.
"It wasn't my finest showing but how do champions respond? They win," Buatsi stated in the ringside as he was greeted with boos from the spectators.
The British fighter bounced back after his maiden career setback - an thrilling contest with Callum Smith in last winter - to secure a twentieth professional win.
Several boxing experts felt Parker, thirty-one, deserved the decision but the British boxer endured the second setback of his 28-fight career.
Buatsi Secures Triumph in Uneventful Affair
Buatsi's progress has stalled in recent times through contract problems and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now stands trying to realize his potential - possibly in what seems like a final roll of the dice - under new promotional backing.
He started carefully, with neither fighter ready to be aggressive in a calculated early stages.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after breaking his hand mid-fight, was participating in his second appearance at the higher weight class.
By the halfway stage, the underdog had made it competitive, creating difficulties for Buatsi, who operated with a solid defense to barely take the better periods.
The crowd's patience decreased during constant clinching, with the challenger slipping to the canvas multiple occasions during grappling.
Parker finished the stronger, but many rounds were hard to judge. However, former world champion Carl Frampton - working with the broadcast network - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
The victor moves on, but with the caliber of heavy hitter Benavidez, and Russian champion Bivol dominating the weight class, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Homage Fuels All-Manchester Fight
In the co-main event, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding local rivalry fight to capture the European light heavyweight belt.
The arena fell silent for a profoundly moving memorial ahead of the contest as a bell ceremony tolled in remembrance of the city's native Hatton, who succumbed 46 years old in September.
It was the premier televised boxing event in the location since the passing of Hatton. As the last bell ended, the quiet gave way to a shout of "there's only one Hatton".
The competition inside the ropes equaled the sentiment. Arthur was knocked down by a significant blow flush on the face in the second round, standing uncertainly to his position on the referee's count.
But the Manchester United-red shorts of the fighter soon advanced again. On the opposite side, Rea - in rival City blue - was marked up soon, significant bruising appearing under his orbital area as the duo exchanged hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with effective uppercuts as the pace hardly diminished over twelve rounds.
Arthur narrowly won the verdict with scoring tallies of even score, narrow lead and clearer margin, but both fighters were relentless and brave, everything their inspiration the legend embodied.
