British light-heavyweight Buatsi made a winning yet underwhelming start 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 seemingly secured him a majority decision in a competitive 10-round bout at the Manchester venue.
But Parker found success, landing some telling single shots in a contest where the techniques failed to mesh, with constant grabbing disrupting the contest.
The officials judged it 96-94 in favor to Buatsi, with the final judge a 95-95.
"It wasn't my finest showing but what do champions do? They prevail," Buatsi commented in the ringside as he was met by disapproval from the audience.
The British fighter got back to winning after his maiden career setback - an memorable fight with his previous opponent in February - to earn a 20th career victory.
Several boxing experts thought Parker, thirty-one, merited the decision but the British boxer experienced the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Uneventful Encounter
Buatsi's progress has slowed in recent years through promotional disputes and long spells of lack of fights.
Earlier forecast as the future of the British fight scene, he now is positioned trying to realize his potential - possibly in what feels like a last chance - under new promotional backing.
He began cautiously, with the two boxers prepared to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in two years ago after suffering a hand injury during the bout, was making just his second appearance at the higher weight class.
By the halfway stage, the underdog had made it competitive, creating difficulties for the favorite, who operated with a solid defense to barely take the better rounds.
The crowd's patience decreased during constant clinching, with the challenger going down various instances during grappling.
The underdog closed well, but many rounds were difficult to score. Although, previous titleholder the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
The victor progresses, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Hatton Homage Inspires Manchester Derby Battle
In the secondary fight, Arthur defeated Bradley Rea by close verdict in a excellent local rivalry battle to win the European light heavyweight belt.
The venue fell silent for a profoundly moving tribute before the fight as a bell ceremony sounded in remembrance of Manchester's own Ricky Hatton, who succumbed 46 years old in recently.
It was the premier televised boxing event in the location since the passing of Hatton. As the last bell ended, the stillness transitioned to a chant of "only one Ricky Hatton".
The action within the ring equaled the feeling. Arthur was floored by a significant blow squarely on the chin in the second round, getting up unsteadily to his footing on the eight count.
But the traditional red equipment of Arthur soon advanced again. Across the ring, Rea - in rival City blue - was marked up quickly, significant bruising appearing under his eye as the fighters landed punishing blows.
Rea, 27, delivered effective strikes but Arthur, 34, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
The victor barely secured the result with official scores of 114-114, narrow lead and 115-112, but the two athletes were relentless and full of heart, everything their idol Hatton embodied.
