British light heavyweight Buatsi secured a victory yet underwhelming beginning 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 majority decision in a competitive ten-round bout at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a contest where the approaches didn't complement each other, with frequent clinching spoiling the fight.
The scoring judges had it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my best showing but what do champions do? They succeed," the victor commented in the ringside as he was greeted with boos from the spectators.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Some ringside observers felt the challenger, thirty-one, merited the victory but the British boxer experienced the second loss of his 28-bout career.
The Champion Earns Triumph in Slow Encounter
The fighter's advancement has stalled in recent years through contract problems and extended periods of inactivity.
Previously predicted as the next star of UK boxing, he now finds himself trying to achieve expectations - possibly in what feels like a ultimate opportunity - under new promotional backing.
He began cautiously, with both competitors prepared to take risks in a cagey opening few rounds.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after damaging his hand mid-fight, was participating in his second appearance at the higher weight class.
By the halfway stage, the underdog had stayed in contention, making life awkward for Buatsi, who operated with a tight guard to narrowly win the cleaner stanzas.
The audience's tolerance decreased amid frequent holding, with the challenger falling to the floor several times during clinches.
The underdog closed well, but many rounds were hard to judge. However, ex-champion Carl Frampton - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Hatton Memorial Motivates Manchester Derby Contest
In the co-main event, Arthur defeated Rea by divided decision in a outstanding all-Manchester battle to win the continental belt.
The arena grew hushed for a deeply poignant homage prior to the bout as a bell ceremony tolled in memory of local hero Ricky Hatton, who succumbed aged 46 in recently.
It was the initial significant broadcast fight night in the urban center since Hatton's death. As the concluding sound disappeared, the stillness transitioned to a shout of "there's just one Hatton".
The competition inside the ropes reflected the feeling. Arthur was sent to the canvas by a powerful punch flush on the face in the initial stage, getting up unsteadily to his position on the referee's count.
But the Manchester United-red attire of the fighter soon came forward again. From the other corner, Rea - in opposing blue - was injured early, significant bruising forming under his eye as the pair traded hard punches.
Rea, twenty-seven, connected with strong blows but Arthur, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over 12 rounds.
Arthur barely secured the result with scoring tallies of 114-114, 115-113 and clearer margin, but the two athletes were relentless and courageous, everything their inspiration Hatton stood for.
