UK light-heavyweight Buatsi secured a victory yet unimpressive debut to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's activity level appeared to earn him a majority decision in a close 10-round fight at the Co-op Live Arena.
But Parker landed significant shots, delivering effective individual punches in a contest where the styles didn't complement each other, with excessive holding spoiling the fight.
The officials judged it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest performance but how do champions respond? They succeed," Buatsi stated in the arena as he was greeted with disapproval from the audience.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in February - to claim a 20th pro success.
Several boxing experts felt Parker, 31, deserved the decision but the Derbyshire fighter endured the second setback of his 28-fight professional journey.
Buatsi Secures Win in Dull Encounter
His career development has plateaued in recent times through promotional disputes and long spells of inactivity.
Once tipped as the future of British boxing, he now finds himself trying to fulfil that early promise - perhaps in what seems like a final roll of the dice - under fresh management.
He began cautiously, with the two boxers willing to take risks in a calculated initial rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second bout at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for Buatsi, who operated with a tight guard to narrowly win the more effective rounds.
The spectators' acceptance diminished because of constant clinching, with Parker falling to the floor multiple occasions during clinches.
The underdog finished the stronger, but multiple periods were hard to judge. However, former world champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
Buatsi progresses, but with the caliber of heavy hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still appears challenging.
Hatton Homage Fuels All-Manchester Battle
In the supporting bout, Arthur beat Bradley Rea by close verdict in a terrific Manchester vs Manchester contest to win the continental championship.
The venue fell silent for a deeply poignant memorial prior to the bout as ten bells sounded in remembrance of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the premier televised boxing event in the city since the passing of Hatton. As the last bell disappeared, the stillness transitioned to a chant of "there's just one Ricky Hatton".
The action inside the ropes matched the emotion. The eventual winner was floored by a left hook squarely on the chin in the second round, rising shakily to his feet on the referee's count.
But the red-colored equipment of the fighter soon pressed ahead again. Across the ring, the opponent - in opposing blue - was marked up early, heavy swelling forming under his eye as the duo exchanged powerful shots.
The challenger, 27, landed power punches but the champion, 34, matched the intensity with powerful upward punches as the action hardly diminished over twelve rounds.
The victor edged the verdict with official scores of 114-114, 115-113 and wider gap, but both fighters were relentless and full of heart, all the qualities their inspiration the legend represented.
