British light heavyweight Buatsi earned a win yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a majority decision in a tight ten-round bout at the boxing arena.
But the challenger landed significant shots, delivering effective single shots in a match where the techniques didn't complement each other, with excessive holding marring the contest.
The officials judged it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my best performance but what do champions do? They win," the victor commented in the ring as he was met by negative reactions from the audience.
The Londoner bounced back after his first professional defeat - an memorable fight with his previous opponent in last winter - to claim a 20th career victory.
Several boxing experts believed the challenger, thirty-one, should have been awarded the victory but the contender endured the second loss of his 28-fight professional journey.
The Champion Secures Win in Uneventful Encounter
The fighter's advancement has plateaued in the past few years through management issues and extended periods of inactivity.
Earlier forecast as the next star of British boxing, he now finds himself trying to achieve expectations - possibly in what appears to be a last chance - under recent support.
He began cautiously, with neither fighter prepared to take risks in a calculated initial rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second appearance at light heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who utilized a solid defense to barely take the cleaner rounds.
The spectators' acceptance diminished because of frequent holding, with Parker going down multiple occasions during grappling.
The underdog ended stronger, but many rounds were hard to judge. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it strongly leaning for Parker, scoring for Buatsi just a single round.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Hatton Memorial Motivates Local Rivalry Contest
In the co-main event, Arthur overcame Rea by divided decision in a excellent local rivalry battle to secure the continental belt.
The venue became quiet for a profoundly moving memorial ahead of the contest as ten bells sounded in memory of Manchester's own Ricky Hatton, who died at age 46 in last month.
It was the initial significant broadcast boxing event in the urban center since Hatton's passing. As the final chime ended, the quiet became a chant of "only one Ricky Hatton".
The action inside the ropes equaled the emotion. Arthur was floored by a powerful punch flush on the chin in the second round, getting up unsteadily to his position on the count of eight.
But the traditional red attire of Arthur soon came forward again. From the other corner, the opponent - in opposing blue - was damaged quickly, heavy swelling developing under his orbital area as the duo exchanged hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, matched the intensity with stinging uppercuts as the pace hardly diminished over the full distance.
Arthur barely secured the verdict with official scores of even score, close margin and clearer margin, but the two athletes were persistent and courageous, everything their inspiration Hatton embodied.
