UK light heavyweight Buatsi made a winning yet underwhelming beginning to his career under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a majority decision in a competitive ten-round bout at the Manchester venue.
But Parker had his moments, connecting with powerful clean blows in a contest where the techniques never quite clicked, with constant grabbing disrupting the fight.
Two judges scored it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my greatest showing but how do champions respond? They succeed," the victor stated in the ringside as he was met by negative reactions from the spectators.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a 20th pro success.
Various analysts thought the challenger, thirty-one, merited the decision but the Derbyshire fighter suffered the second setback of his 28-bout professional journey.
Buatsi Earns Win in Dull Encounter
His career development has slowed in the past few years through contract problems and extended periods of inactivity.
Previously predicted as the next star of British boxing, he now finds himself trying to achieve expectations - possibly in what seems like a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers ready to take risks in a cagey early stages.
Parker, whose single earlier setback came at super middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was competing in only his second bout at light heavyweight.
By the halfway stage, Parker had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to edge the more effective rounds.
The spectators' acceptance decreased because of constant clinching, with the challenger falling to the floor several times during grappling.
Parker closed well, but many rounds were challenging to assess. Nevertheless, former world champion the boxing analyst - commentating on Dazn - had it particularly wide for the challenger, giving Buatsi just only one stanza.
Buatsi progresses, but with the caliber of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a excellent all-Manchester battle to win the European light heavyweight title.
The stadium grew hushed for a deeply poignant memorial prior to the bout as a bell ceremony sounded in memory of local hero Ricky Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the concluding sound disappeared, the silence transitioned to a roar of "only one Hatton".
The action inside the ropes matched the emotion. The eventual winner was floored by a powerful punch flush on the jaw in the initial stage, rising shakily to his footing on the eight count.
But the red-colored equipment of the fighter soon pressed ahead again. On the opposite side, the opponent - in rival City blue - was damaged early, noticeable damage appearing under his orbital area as the duo landed hard punches.
Rea, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity hardly diminished over the full distance.
The victor barely secured the verdict with official scores of 114-114, close margin and clearer margin, but each competitor were determined and full of heart, everything their idol the legend stood for.
