British light-heavyweight Buatsi earned a win yet disappointing debut to his career under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a split decision in a close 10-round bout at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful clean blows in a match where the styles didn't complement each other, with excessive holding spoiling the contest.
The officials scored it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my best performance but how do champions respond? They succeed," Buatsi stated in the arena as he was met by disapproval from the spectators.
The Londoner got back to winning after his first professional defeat - an epic battle with Callum Smith in last winter - to claim a twentieth professional win.
Some ringside observers felt Parker, thirty-one, deserved the win but the Derbyshire fighter experienced the second defeat of his 28-bout career.
Buatsi Claims Victory in Uneventful Match
The fighter's advancement has slowed in the past few years through management issues and considerable time of inactivity.
Earlier forecast as the next star of British boxing, he now stands trying to achieve expectations - perhaps in what feels like a last chance - under new promotional backing.
He began cautiously, with the two boxers prepared to be aggressive in a tentative early stages.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after damaging his hand in the contest, was making just his second appearance at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for the favorite, who utilized a solid defense to edge the better stanzas.
The crowd's patience diminished amid frequent holding, with the challenger going down various instances during close exchanges.
The underdog closed well, but multiple periods were difficult to score. Nevertheless, previous titleholder the boxing analyst - working with Dazn - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
The victor advances, but with the caliber of hard hitter Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Hatton Homage Motivates All-Manchester Fight
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a excellent Manchester vs Manchester fight to win the continental title.
The venue became quiet for a profoundly moving homage ahead of the contest as 10 bells rang in memory of the city's native Ricky Hatton, who succumbed at age 46 in last month.
It was the first major televised match card in the city since Hatton's passing. As the last bell ended, the silence gave way to a chant of "there's just one Ricky Hatton".
The action inside the ropes equaled the sentiment. Arthur was floored by a significant blow squarely on the chin in the initial stage, getting up unsteadily to his feet on the eight count.
But the traditional red equipment of the fighter soon pressed ahead again. Across the ring, Rea - in opposing blue - was marked up quickly, significant bruising developing under his orbital area as the duo exchanged hard punches.
The challenger, 27, landed power punches but Arthur, thirty-four, matched the intensity with effective uppercuts as the pace hardly diminished over twelve rounds.
Arthur edged the verdict with scoring tallies of draw, close margin and wider gap, but each competitor were determined and full of heart, everything their hero the legend represented.
