UK light-heavyweight Buatsi made a winning yet unimpressive debut to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a competitive 10-round fight at the boxing arena.
But Parker had his moments, delivering effective clean blows in a fight where the techniques didn't complement each other, with excessive holding disrupting the action.
Two judges scored it 96-94 for to Buatsi, with the third a even score.
"It wasn't my greatest display but what do champions do? They prevail," the victor stated in the ringside as he was met by boos from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Various analysts believed Parker, thirty-one, deserved the win but the British boxer endured the second loss of his 28-bout professional journey.
Buatsi Claims Win in Uneventful Encounter
His career development has stalled in the past few years through contract problems and extended periods of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to realize his potential - perhaps in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter prepared to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was competing in only his second bout at light-heavyweight.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who worked behind a solid defense to narrowly win the more effective periods.
The spectators' acceptance wore thin because of regular grabbing, with the challenger falling to the floor several times during clinches.
The underdog finished the stronger, but multiple periods were difficult to score. Nevertheless, previous titleholder Carl Frampton - working with Dazn - had it particularly wide for the challenger, giving Buatsi just only one stanza.
The victor moves on, but with the presence of heavy hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - judging by this showing - still looks steep.
Ricky Hatton Homage Motivates Local Rivalry Battle
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a terrific local rivalry fight to secure the European light-heavyweight title.
The stadium became quiet for a deeply poignant memorial prior to the bout as ten bells sounded in honor of the city's native Hatton, who died aged 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's passing. As the concluding sound disappeared, the silence gave way to a chant of "there's only one Hatton".
The fighting inside the ropes reflected the emotion. Arthur was sent to the canvas by a significant blow flush on the jaw in the initial stage, standing uncertainly to his footing on the eight count.
But the red-colored shorts of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was injured early, noticeable damage developing under his orbital area as the fighters exchanged hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, fought fire with fire with powerful upward punches as the intensity hardly diminished over 12 rounds.
Arthur edged the result with official scores of even score, 115-113 and 115-112, but each competitor were persistent and full of heart, exactly what their inspiration Hatton embodied.
