British light-heavyweight Buatsi earned a win yet disappointing beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a majority decision in a competitive ten-round fight at the boxing arena.
But the challenger had his moments, delivering effective single shots in a contest where the styles didn't complement each other, with constant grabbing marring the fight.
The officials scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest display but what do champions do? They prevail," Buatsi said in the ring as he was greeted with negative reactions from the spectators.
The British fighter returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, deserved the win but the contender suffered the second defeat of his 28-bout professional journey.
Buatsi Claims Triumph in Slow Affair
The fighter's advancement has slowed in the past few years through contract problems and considerable time of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with the two boxers prepared to be aggressive in a cagey opening few rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was making just his second appearance at light heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who worked behind a tight guard to narrowly win the more effective periods.
The spectators' acceptance diminished because of constant clinching, with the challenger going down various instances during close exchanges.
Parker ended stronger, but many rounds were hard to judge. Although, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of hard hitter David Benavidez, and Russian star Dmitry Bivol leading the category, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Homage Inspires All-Manchester Contest
In the secondary fight, Arthur defeated Bradley Rea by split-decision in a outstanding Manchester vs Manchester contest to secure the continental championship.
The stadium fell silent for a deeply poignant tribute prior to the bout as a bell ceremony tolled in remembrance of the city's native Ricky Hatton, who succumbed aged 46 in last month.
It was the first major televised match card in the urban center since Hatton's death. As the last bell ended, the quiet gave way to a chant of "only one Hatton".
The action during the bout matched the feeling. Arthur was sent to the canvas by a left hook directly to the chin in the second round, getting up unsteadily to his footing on the referee's count.
But the red-colored equipment of Arthur soon came forward again. Across the ring, the opponent - in rival City blue - was injured quickly, noticeable damage forming under his orbital area as the fighters traded hard punches.
Rea, 27, landed power punches but Arthur, 34, matched the intensity with powerful upward punches as the pace hardly diminished over the full distance.
The victor narrowly won the result with official scores of draw, narrow lead and 115-112, but both fighters were determined and brave, all the qualities their hero the legend represented.
