UK light-heavyweight Buatsi secured a victory yet unimpressive start to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's activity level likely gained him a majority decision in a competitive 10-round contest at the Manchester venue.
But the challenger landed significant shots, delivering effective individual punches in a fight where the styles failed to mesh, with excessive holding marring the contest.
The officials scored it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my greatest showing but what defines champions? They win," the victor stated in the arena as he was met by negative reactions from the crowd.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in February - to claim a twentieth professional win.
Several boxing experts believed the challenger, 31, merited the victory but the Derbyshire fighter experienced the second defeat of his 28-fight professional journey.
Buatsi Earns Victory in Slow Affair
The fighter's advancement has slowed in the past few years through contract problems and long spells of lack of fights.
Once tipped as the future of UK boxing, he now stands trying to fulfil that early promise - perhaps in what seems like a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter ready to be aggressive in a calculated opening few rounds.
Parker, whose single earlier setback 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 the higher weight class.
By the halfway stage, the underdog had kept it close, making life awkward for Buatsi, who operated with a protective stance to barely take the cleaner periods.
The audience's tolerance diminished amid regular grabbing, with Parker falling to the floor multiple occasions during grappling.
The underdog ended stronger, but several stanzas were difficult to score. Although, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, giving Buatsi just one round.
Buatsi advances, but with the likes of heavy hitter Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Memorial Inspires Local Rivalry Battle
In the co-main event, Lyndon Arthur defeated Bradley Rea by close verdict in a outstanding Manchester vs Manchester contest to secure the European light-heavyweight title.
The arena grew hushed for a profoundly moving memorial ahead of the contest as ten bells tolled in memory of the city's native Hatton, who succumbed 46 years old in September.
It was the first major televised boxing event in the urban center since Hatton's passing. As the final chime disappeared, the quiet gave way to a roar of "there's just one Ricky Hatton".
The action inside the ropes reflected the emotion. The eventual winner was knocked down by a left hook directly to the jaw in the initial stage, standing uncertainly to his feet on the count of eight.
But the Manchester United-red attire of Arthur soon came forward again. Across the ring, Rea - in opposing blue - was damaged quickly, significant bruising forming under his eye as the fighters traded hard punches.
Rea, 27, delivered effective strikes but the champion, thirty-four, responded in kind with effective uppercuts as the intensity hardly diminished over 12 rounds.
Arthur barely secured the decision with scoring tallies of draw, close margin and wider gap, but the two athletes were relentless and brave, all the qualities their inspiration the legend stood for.
