British light heavyweight Buatsi secured a victory yet disappointing beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a majority decision in a tight 10-round contest at the boxing arena.
But Parker found success, delivering effective clean blows in a fight where the styles failed to mesh, with excessive holding disrupting the contest.
The officials scored it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my best performance but how do champions respond? They succeed," the victor commented in the arena as he was greeted with disapproval from the audience.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts felt the challenger, 31, deserved the decision but the British boxer endured the second loss of his 28-fight professional journey.
The Champion Earns Win in Uneventful Encounter
His career development has stalled in recent times through contract problems and considerable time of inactivity.
Earlier forecast as the rising talent of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a final roll of the dice - under new promotional backing.
He started carefully, with both competitors willing to take risks in a tentative initial rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after breaking his hand mid-fight, was competing in only his second bout at the higher weight class.
By the fight's midpoint, the underdog had stayed in contention, creating difficulties for Buatsi, who worked behind a solid defense to edge the better periods.
The spectators' acceptance diminished during regular grabbing, with Parker going down various instances during clinches.
Parker ended stronger, but multiple periods were difficult to score. Nevertheless, ex-champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for Parker, scoring for Buatsi just a single round.
The victor progresses, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - based on this performance - still appears challenging.
Hatton Homage Motivates Manchester Derby Battle
In the secondary fight, Arthur defeated Rea by divided decision in a excellent all-Manchester battle to win the European light heavyweight championship.
The stadium became quiet for a extremely emotional homage ahead of the contest as ten bells rang in remembrance of Manchester's own Ricky Hatton, who died aged 46 in last month.
It was the premier televised match card in the urban center since the passing of Hatton. As the last bell ended, the quiet gave way to a chant of "there's only one Ricky Hatton".
The fighting within the ring equaled the emotion. The eventual winner was floored by a powerful punch squarely on the jaw in the early round, getting up unsteadily to his footing on the count of eight.
But the traditional red shorts of the fighter soon pressed ahead again. From the other corner, the opponent - in opposing blue - was marked up early, significant bruising appearing under his eye as the duo exchanged powerful shots.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with powerful upward punches as the intensity hardly diminished over twelve rounds.
Arthur narrowly won the result with scoring tallies of even score, close margin and clearer margin, but each competitor were determined and brave, everything their hero Hatton embodied.
