British light-heavyweight Buatsi secured a victory yet unimpressive beginning to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a competitive ten-round fight at the Co-op Live Arena.
But the challenger had his moments, connecting with powerful clean blows in a match where the techniques failed to mesh, with excessive holding spoiling the contest.
Two judges judged it 96-94 for to the winner, with the third a 95-95.
"It wasn't my greatest showing but how do champions respond? They succeed," the victor stated in the arena as he was greeted with boos from the audience.
The Londoner returned to winning ways after his first professional defeat - an epic battle with Callum Smith in February - to earn a 20th career victory.
Some ringside observers thought Parker, thirty-one, should have been awarded the victory but the Derbyshire fighter endured the second defeat of his 28-fight career.
The Champion Secures Triumph in Dull Affair
His career development has stalled in recent years through contract problems and extended periods of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to fulfil that early promise - possibly in what appears to be a last chance - under new promotional backing.
He began cautiously, with neither fighter willing to be aggressive in a tentative opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after suffering a hand injury mid-fight, was competing in only his second appearance at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who utilized a tight guard to narrowly win the more effective stanzas.
The crowd's patience wore thin because of frequent holding, with the challenger falling to the floor multiple occasions during clinches.
The underdog ended stronger, but several stanzas were difficult to score. Although, ex-champion the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just one round.
The victor moves on, but with the presence of power puncher David Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - on this evidence - still appears challenging.
Ricky Hatton Homage Fuels Manchester Derby Contest
In the supporting bout, Arthur defeated Bradley Rea by split-decision in a terrific all-Manchester battle to win the continental title.
The arena fell silent for a profoundly moving memorial before the fight as a bell ceremony tolled in memory of local hero Hatton, who succumbed at age 46 in September.
It was the premier televised fight night in the city since the passing of Hatton. As the concluding sound faded, the stillness gave way to a roar of "only one Hatton".
The competition within the ring reflected the sentiment. Arthur was knocked down by a significant blow flush on the jaw in the second round, standing uncertainly to his position on the count of eight.
But the traditional red attire of the fighter soon advanced again. On the opposite side, the opponent - in opposing blue - was marked up early, heavy swelling appearing under his orbital area as the duo landed powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with effective uppercuts as the intensity seldom decreased over twelve rounds.
Arthur narrowly won the result with official scores of 114-114, 115-113 and clearer margin, but the two athletes were relentless and courageous, exactly what their inspiration the legend represented.
