UK light heavyweight Buatsi made a winning yet disappointing debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But the challenger landed significant shots, connecting with powerful individual punches in a fight where the techniques failed to mesh, with constant grabbing disrupting the contest.
The scoring judges scored it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my greatest performance but what defines champions? They prevail," the victor stated in the ringside as he was faced negative reactions from the audience.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Some ringside observers believed Parker, thirty-one, deserved the victory but the British boxer suffered the second defeat of his 28-bout career.
The Champion Claims Triumph in Uneventful Encounter
The fighter's advancement has plateaued in recent times through promotional disputes and considerable time of inactivity.
Once tipped as the future of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what appears to be a last chance - under recent support.
He opened tentatively, with neither fighter willing to overcommit in a tentative early stages.
Parker, whose only previous defeat came at the lower weight class against John Ryder in two years ago after breaking his hand in the contest, was competing in only his second bout at the higher weight class.
By the middle rounds, the underdog had kept it close, creating difficulties for the favorite, who operated with a tight guard to narrowly win the cleaner stanzas.
The spectators' acceptance diminished amid frequent holding, with Parker falling to the floor several times during grappling.
The underdog closed well, but multiple periods were hard to judge. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just one round.
The victor advances, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still seems difficult.
Ricky Hatton Tribute Fuels All-Manchester Battle
In the supporting bout, Arthur beat Bradley Rea by close verdict in a terrific all-Manchester fight to secure the continental belt.
The venue became quiet for a extremely emotional tribute prior to the bout as ten bells sounded in remembrance of local hero Hatton, who succumbed 46 years old in recently.
It was the first major televised boxing event in the city since the passing of Hatton. As the last bell faded, the silence became a shout of "there's only one Hatton".
The fighting inside the ropes reflected the emotion. Arthur was floored by a powerful punch directly to the face in the second round, rising shakily to his position on the eight count.
But the traditional red equipment of Arthur soon came forward again. On the opposite side, the opponent - in opposing blue - was injured soon, significant bruising developing under his face as the duo landed punishing blows.
The challenger, twenty-seven, landed power punches but the champion, 34, fought fire with fire with effective uppercuts as the intensity seldom decreased over twelve rounds.
Arthur edged the result with scoring tallies of even score, narrow lead and 115-112, but each competitor were relentless and brave, everything their idol Hatton represented.
