UK light heavyweight Buatsi made a winning yet unimpressive debut to life under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a split decision in a tight ten-round bout at the boxing arena.
But Parker found success, connecting with powerful single shots in a contest where the approaches didn't complement each other, with constant grabbing disrupting the action.
Two judges had it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my greatest performance but how do champions respond? They win," Buatsi stated in the ring as he was met by disapproval from the crowd.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in last winter - to secure a 20th pro success.
Some ringside observers thought the challenger, 31, should have been awarded the win but the British boxer endured the second loss of his 28-fight professional journey.
Buatsi Secures Triumph in Uneventful Affair
His career development has plateaued in recent times through promotional disputes and extended periods of lack of fights.
Once tipped as the future of UK boxing, he now finds himself trying to realize his potential - perhaps in what seems like a final roll of the dice - under recent support.
He opened tentatively, with both competitors ready to overcommit in a tentative initial rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in two years ago after damaging his hand in the contest, was making just his second appearance at light heavyweight.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who worked behind a tight guard to edge the more effective rounds.
The spectators' acceptance wore thin amid constant clinching, with the challenger going down several times during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just one round.
The victor progresses, but with the caliber of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Hatton Memorial Inspires All-Manchester Contest
In the secondary fight, Arthur beat Bradley Rea by close verdict in a excellent all-Manchester battle to secure the continental title.
The venue grew hushed for a profoundly moving tribute ahead of the contest as 10 bells rang in remembrance of Manchester's own Ricky Hatton, who passed away 46 years old in recently.
It was the first major televised match card in the location since Hatton's death. As the final chime ended, the silence became a roar of "there's only one Ricky Hatton".
The action inside the ropes reflected the feeling. Arthur was knocked down by a powerful punch squarely on the face in the second round, standing uncertainly to his position on the referee's count.
But the red-colored attire of Arthur soon came forward again. On the opposite side, the opponent - in competitive blue - was injured early, heavy swelling appearing under his orbital area as the duo landed powerful shots.
The challenger, 27, connected with strong blows but Arthur, 34, responded in kind with stinging uppercuts as the intensity hardly diminished over 12 rounds.
Arthur narrowly won the verdict with official scores of 114-114, 115-113 and wider gap, but each competitor were relentless and full of heart, exactly what their inspiration Hatton embodied.
