British light-heavyweight Buatsi made a winning yet underwhelming beginning to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a majority decision in a close ten-round contest at the boxing arena.
But the challenger had his moments, landing some telling clean blows in a match where the styles didn't complement each other, with constant grabbing marring the action.
The scoring judges had it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my best showing but what do champions do? They win," Buatsi said in the arena as he was greeted with disapproval from the spectators.
The British fighter bounced back after his first professional defeat - an memorable fight with Callum Smith in last winter - to secure a twentieth professional win.
Various analysts felt Parker, thirty-one, deserved the victory but the British boxer endured the second defeat of his 28-match professional journey.
The Champion Secures Victory in Uneventful Encounter
His career development has plateaued in recent times through management issues and considerable time of inactivity.
Earlier forecast as the future of UK boxing, he now finds himself trying to achieve expectations - perhaps in what appears to be a last chance - under recent support.
He opened tentatively, with neither fighter willing to take risks in a tentative opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in two years ago after suffering a hand injury during the bout, was competing in only his second appearance at the higher weight class.
By the halfway stage, the underdog had made it competitive, creating difficulties for the favorite, who utilized a solid defense to edge the better periods.
The spectators' acceptance diminished amid constant clinching, with Parker falling to the floor several times during grappling.
The underdog finished the stronger, but many rounds were hard to judge. Although, former world champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just only one stanza.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Tribute Fuels All-Manchester Contest
In the secondary fight, Arthur beat Bradley Rea by close verdict in a outstanding Manchester vs Manchester contest to win the European light-heavyweight belt.
The stadium grew hushed for a extremely emotional memorial prior to the bout as a bell ceremony rang in honor of Manchester's own Hatton, who died 46 years old in September.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the last bell faded, the silence transitioned to a shout of "there's only one Ricky Hatton".
The action within the ring equaled the feeling. Arthur was floored by a significant blow directly to the jaw in the initial stage, standing uncertainly to his footing on the eight count.
But the red-colored shorts of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was marked up soon, noticeable damage developing under his face as the duo traded hard punches.
The challenger, 27, landed power punches but Arthur, thirty-four, responded in kind with powerful upward punches as the action rarely dropped over twelve rounds.
Arthur narrowly won the result with official scores of draw, close margin and 115-112, but each competitor were relentless and full of heart, everything their inspiration Hatton stood for.
