UK light heavyweight Buatsi made a winning yet unimpressive beginning to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's activity level appeared to earn him a majority decision in a tight 10-round bout at the Co-op Live Arena.
But the challenger found success, landing some telling clean blows in a fight where the approaches never quite clicked, with excessive holding disrupting the fight.
The officials judged it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest display but how do champions respond? They prevail," Buatsi commented in the ringside as he was greeted with boos from the crowd.
The Londoner got back to winning after his maiden career setback - an epic battle with Callum Smith in February - to claim a 20th pro success.
Some ringside observers thought Parker, 31, should have been awarded the win but the contender experienced the second defeat of his 28-fight professional journey.
The Champion Earns Triumph in Uneventful Affair
The fighter's advancement has slowed in recent years through promotional disputes and long spells of inactivity.
Previously predicted as the future of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what appears to be a last chance - under new promotional backing.
He started carefully, with neither fighter ready to be aggressive in a calculated initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after breaking his hand during the bout, was competing in only his second appearance at light-heavyweight.
By the halfway stage, Parker had kept it close, making life awkward for Buatsi, who worked behind a protective stance to edge the better rounds.
The audience's tolerance wore thin amid frequent holding, with the challenger slipping to the canvas multiple occasions during grappling.
The underdog closed well, but multiple periods were hard to judge. Although, former world champion the boxing analyst - commentating on Dazn - had it particularly wide for Parker, awarding Buatsi just only one stanza.
The victor progresses, but with the caliber of hard hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Homage Fuels Manchester Derby Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a terrific local rivalry fight to secure the continental belt.
The stadium became quiet for a extremely emotional homage before the fight as 10 bells sounded in remembrance of local hero Ricky Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast boxing event in the urban center since Hatton's passing. As the last bell faded, the stillness gave way to a roar of "only one Hatton".
The fighting during the bout equaled the sentiment. The eventual winner was floored by a left hook directly to the chin in the early round, rising shakily to his footing on the referee's count.
But the traditional red equipment of Arthur soon came forward again. From the other corner, Rea - in rival City blue - was marked up quickly, noticeable damage developing under his face as the pair exchanged punishing blows.
The challenger, 27, landed power punches but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the intensity rarely dropped over 12 rounds.
Arthur edged the verdict with judges scorecards of even score, close margin and wider gap, but each competitor were persistent and courageous, all the qualities their inspiration Hatton represented.
