UK light-heavyweight Buatsi made a winning yet unimpressive start to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a split decision in a tight ten-round contest at the Manchester venue.
But the challenger found success, landing some telling clean blows in a match where the techniques failed to mesh, with constant grabbing marring the fight.
The scoring judges judged it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest performance but how do champions respond? They succeed," the victor said in the arena as he was met by negative reactions from the spectators.
The Londoner returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in February - to secure a 20th career victory.
Some ringside observers believed Parker, thirty-one, should have been awarded the decision but the contender suffered the second loss of his 28-fight professional journey.
Buatsi Earns Win in Dull Encounter
His career development has stalled in the past few years through promotional disputes and extended periods of inactivity.
Once tipped as the next star of British boxing, he now finds himself trying to fulfil that early promise - maybe in what feels like a final roll of the dice - under recent support.
He started carefully, with neither fighter willing to overcommit in a calculated initial rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was competing in only his second bout at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the more effective stanzas.
The audience's tolerance wore thin amid regular grabbing, with Parker going down several times during grappling.
The underdog closed well, but many rounds were difficult to score. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
The victor progresses, but with the likes of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Hatton Homage Inspires All-Manchester Fight
In the secondary fight, Arthur defeated Rea by split-decision in a terrific Manchester vs Manchester fight to win the European light heavyweight championship.
The arena became quiet for a profoundly moving tribute before the fight as a bell ceremony sounded in honor of local hero Hatton, who succumbed aged 46 in last month.
It was the premier televised fight night in the urban center since Hatton's death. As the last bell ended, the silence became a roar of "there's only one Ricky Hatton".
The action during the bout equaled the feeling. Arthur was knocked down by a left hook directly to the face in the second round, rising shakily to his footing on the eight count.
But the traditional red attire of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was damaged quickly, significant bruising developing under his eye as the pair landed hard punches.
Rea, 27, landed power punches but the champion, 34, responded in kind with effective uppercuts as the action hardly diminished over the full distance.
The victor barely secured the verdict with judges scorecards of draw, narrow lead and 115-112, but the two athletes were determined and full of heart, all the qualities their idol Hatton represented.
