British light heavyweight Buatsi earned a win yet unimpressive start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a judges' verdict in a competitive 10-round fight at the boxing arena.
But Parker had his moments, delivering effective individual punches in a match where the techniques failed to mesh, with frequent clinching disrupting the fight.
The officials had it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my finest display but what do champions do? They succeed," Buatsi stated in the ringside as he was faced boos from the spectators.
The Londoner got back to winning after his maiden career setback - an thrilling contest with Callum Smith in February - to secure a 20th pro success.
Various analysts felt the challenger, thirty-one, deserved the victory but the British boxer endured the second setback of his 28-fight career.
The Champion Earns Triumph in Uneventful Encounter
Buatsi's progress has plateaued in recent times through contract problems and considerable time of inactivity.
Earlier forecast as the next star of the British fight scene, he now stands trying to achieve expectations - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers ready to overcommit in a tentative early stages.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was competing in only his second bout at light heavyweight.
By the halfway stage, Parker had made it competitive, causing problems for Buatsi, who utilized a protective stance to barely take the more effective rounds.
The audience's tolerance decreased during regular grabbing, with Parker falling to the floor multiple occasions during clinches.
Parker closed well, but multiple periods were hard to judge. Although, ex-champion the boxing analyst - commentating on Dazn - had it significantly in favor for Parker, giving Buatsi just only one stanza.
The victor advances, but with the caliber of power puncher Benavidez, and Russian star Bivol leading the category, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Battle
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a terrific all-Manchester battle to secure the European light-heavyweight championship.
The arena fell silent for a profoundly moving tribute prior to the bout as ten bells tolled in remembrance of local hero Hatton, who succumbed aged 46 in recently.
It was the initial significant broadcast match card in the city since Hatton's passing. As the concluding sound ended, the stillness transitioned to a shout of "there's only one Hatton".
The action during the bout equaled the sentiment. Arthur was knocked down by a left hook squarely on the jaw in the early round, standing uncertainly to his position on the eight count.
But the traditional red attire of Arthur soon came forward again. Across the ring, Rea - in competitive blue - was marked up early, noticeable damage forming under his face as the pair landed hard punches.
Rea, 27, connected with strong blows but the champion, thirty-four, fought fire with fire with powerful upward punches as the action rarely dropped over 12 rounds.
The victor edged the verdict with scoring tallies of 114-114, narrow lead and clearer margin, but both fighters were persistent and courageous, all the qualities their hero the legend embodied.
