British light heavyweight Buatsi secured a victory yet unimpressive start to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a close 10-round bout at the Manchester venue.
But Parker found success, delivering effective clean blows in a match where the styles didn't complement each other, with frequent clinching spoiling the fight.
Two judges had it 96-94 for to Buatsi, with the final judge a 95-95.
"It wasn't my greatest display but how do champions respond? They win," the victor said in the ringside as he was met by negative reactions from the audience.
The British fighter bounced back after his first professional defeat - an epic battle with Callum Smith in last winter - to claim a twentieth professional win.
Some ringside observers thought Parker, thirty-one, should have been awarded the win but the British boxer suffered the second setback of his 28-fight professional journey.
The Champion Claims Triumph in Uneventful Match
The fighter's advancement has stalled in recent times through management issues and considerable time of inactivity.
Earlier forecast as the future of UK boxing, he now is positioned trying to achieve expectations - maybe in what seems like a last chance - under new promotional backing.
He started carefully, with both competitors willing to take risks in a calculated early stages.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had made it competitive, creating difficulties for Buatsi, who utilized a tight guard to edge the cleaner periods.
The spectators' acceptance wore thin amid constant clinching, with Parker going down various instances during clinches.
The underdog ended stronger, but several stanzas were hard to judge. Although, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, giving Buatsi just one round.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Homage Fuels Local Rivalry Contest
In the supporting bout, Arthur overcame Rea by split-decision in a outstanding local rivalry battle to win the European light heavyweight title.
The venue fell silent for a deeply poignant memorial ahead of the contest as a bell ceremony rang in memory of Manchester's own Ricky Hatton, who died aged 46 in last month.
It was the premier televised match card in the location since the passing of Hatton. As the concluding sound ended, the quiet became a shout of "only one Ricky Hatton".
The action during the bout matched the emotion. The eventual winner was sent to the canvas by a significant blow flush on the jaw in the early round, getting up unsteadily to his footing on the referee's count.
But the traditional red equipment of Arthur soon advanced again. Across the ring, the opponent - in opposing blue - was injured quickly, heavy swelling forming under his face as the duo exchanged powerful shots.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, fought fire with fire with effective uppercuts as the action seldom decreased over the full distance.
Arthur edged the decision with official scores of 114-114, close margin and clearer margin, but both fighters were relentless and courageous, exactly what their idol Hatton stood for.
