British light-heavyweight Buatsi earned a win yet unimpressive beginning to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a tight 10-round contest at the Co-op Live Arena.
But the challenger found success, landing some telling single shots in a contest where the approaches failed to mesh, with excessive holding spoiling the contest.
The scoring judges scored it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my finest display but what defines champions? They prevail," the victor stated in the ring as he was faced disapproval from the crowd.
The Londoner got back to winning after his initial pro loss - an epic battle with Callum Smith in February - to secure a 20th career victory.
Several boxing experts thought the challenger, 31, should have been awarded the win but the Derbyshire fighter suffered the second loss of his 28-bout professional journey.
The Champion Secures Triumph in Uneventful Match
Buatsi's progress has plateaued in recent years through promotional disputes and long spells of lack of fights.
Previously predicted as the next star of the British fight scene, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter ready to be aggressive in a tentative initial rounds.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in two years ago after breaking his hand in the contest, was making just his second appearance at light heavyweight.
By the halfway stage, Parker had stayed in contention, causing problems for Buatsi, who utilized a tight guard to barely take the more effective rounds.
The audience's tolerance wore thin during regular grabbing, with Parker going down various instances during clinches.
Parker ended stronger, but several stanzas were difficult to score. However, ex-champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, awarding Buatsi just only one stanza.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the road to world glory - on this evidence - still appears challenging.
Ricky Hatton Memorial Fuels All-Manchester Fight
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a outstanding all-Manchester battle to win the European light-heavyweight championship.
The arena grew hushed for a extremely emotional tribute prior to the bout as ten bells sounded in remembrance of local hero Ricky Hatton, who passed away aged 46 in last month.
It was the premier televised fight night in the location since Hatton's passing. As the final chime ended, the quiet transitioned to a shout of "there's just one Ricky Hatton".
The fighting within the ring reflected the sentiment. Arthur was sent to the canvas by a left hook flush on the chin in the early round, getting up unsteadily to his position on the eight count.
But the traditional red attire of the fighter soon came forward again. Across the ring, Rea - in opposing blue - was marked up quickly, significant bruising appearing under his eye as the pair landed powerful shots.
Rea, twenty-seven, landed power punches but the champion, 34, fought fire with fire with effective uppercuts as the intensity hardly diminished over twelve rounds.
The victor barely secured the verdict with scoring tallies of even score, narrow lead and wider gap, but each competitor were persistent and brave, exactly what their inspiration Hatton stood for.
