UK light heavyweight Buatsi secured a victory yet unimpressive beginning to his career under recent management with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a judges' verdict in a competitive ten-round contest at the Co-op Live Arena.
But the challenger had his moments, connecting with powerful clean blows in a contest where the techniques never quite clicked, with frequent clinching marring the contest.
Two judges judged it 96-94 in favor to the winner, with the third a even score.
"It wasn't my finest showing but how do champions respond? They win," Buatsi said in the ring as he was met by negative reactions from the audience.
The Londoner returned to winning ways after his first professional defeat - an epic battle with Callum Smith in February - to earn a 20th pro success.
Several boxing experts felt Parker, 31, should have been awarded the victory but the contender endured the second loss of his 28-fight career.
Buatsi Earns Victory in Uneventful Encounter
His career development has plateaued in the past few years through contract problems and extended periods of inactivity.
Once tipped as the future of British boxing, he now finds himself trying to achieve expectations - perhaps in what feels like a last chance - under new promotional backing.
He began cautiously, with both competitors prepared to take risks in a cagey initial rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after breaking his hand mid-fight, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, Parker had made it competitive, causing problems for the favorite, who utilized a protective stance to narrowly win the better rounds.
The audience's tolerance diminished amid frequent holding, with the challenger going down multiple occasions during grappling.
Parker ended stronger, but multiple periods were challenging to assess. However, ex-champion Carl Frampton - commentating on Dazn - had it strongly leaning for Parker, scoring for Buatsi just one round.
The victor moves on, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Memorial Inspires Manchester Derby Fight
In the co-main event, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester contest to win the continental championship.
The venue became quiet for a profoundly moving homage ahead of the contest as a bell ceremony tolled in honor of Manchester's own Ricky Hatton, who succumbed 46 years old in September.
It was the first major televised fight night in the city since Hatton's death. As the concluding sound disappeared, the silence transitioned to a roar of "there's just one Hatton".
The action during the bout reflected the emotion. Arthur was knocked down by a powerful punch squarely on the chin in the second round, getting up unsteadily to his footing on the count of eight.
But the traditional red equipment of Arthur soon came forward again. From the other corner, the opponent - in rival City blue - was damaged quickly, heavy swelling appearing under his eye as the fighters traded hard punches.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with stinging uppercuts as the pace hardly diminished over the full distance.
The victor edged the verdict with scoring tallies of 114-114, 115-113 and 115-112, but the two athletes were relentless and brave, exactly what their idol Hatton embodied.
