British light-heavyweight Buatsi earned a win yet unimpressive debut to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a majority decision in a close ten-round fight at the Co-op Live Arena.
But Parker had his moments, delivering effective individual punches in a fight where the approaches never quite clicked, with excessive holding disrupting the fight.
The officials scored it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest display but what do champions do? They win," the victor stated in the arena as he was greeted with disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts felt Parker, thirty-one, deserved the decision but the contender endured the second loss of his 28-fight career.
The Champion Earns Triumph in Dull Match
The fighter's advancement has stalled in recent times through management issues and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now stands trying to fulfil that early promise - perhaps in what feels like a last chance - under recent support.
He started carefully, with both competitors ready to be aggressive in a tentative initial rounds.
Parker, whose only previous defeat came at the lower weight class against John Ryder in two years ago after suffering a hand injury during the bout, was participating in his second bout at light heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who utilized a tight guard to barely take the cleaner stanzas.
The crowd's patience wore thin amid frequent holding, with the challenger slipping to the canvas several times during close exchanges.
Parker closed well, but multiple periods were challenging to assess. Although, ex-champion the boxing analyst - working with Dazn - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - based on this performance - still seems difficult.
Hatton Tribute Fuels Manchester Derby Fight
In the supporting bout, Lyndon Arthur overcame Bradley Rea by split-decision in a outstanding Manchester vs Manchester battle to capture the European light heavyweight championship.
The arena fell silent for a deeply poignant homage prior to the bout as 10 bells rang in honor of local hero Hatton, who passed away 46 years old in recently.
It was the premier televised fight night in the city since Hatton's passing. As the concluding sound ended, the quiet gave way to a roar of "there's only one Ricky Hatton".
The competition within the ring reflected the emotion. The eventual winner was floored by a significant blow squarely on the chin in the initial stage, rising shakily to his position on the eight count.
But the traditional red shorts of the fighter soon came forward again. Across the ring, Rea - in opposing blue - was damaged early, heavy swelling forming under his eye as the fighters landed punishing blows.
Rea, 27, delivered effective strikes but Arthur, thirty-four, fought fire with fire with effective uppercuts as the pace rarely dropped over the full distance.
Arthur edged the result with judges scorecards of draw, 115-113 and 115-112, but both fighters were persistent and brave, exactly what their inspiration Hatton represented.
