UK light heavyweight Buatsi secured a victory yet unimpressive debut to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a close 10-round fight at the Manchester venue.
But the challenger had his moments, delivering effective single shots in a contest where the styles never quite clicked, with constant grabbing spoiling the action.
The officials judged it 96-94 for to Buatsi, with the third a even score.
"It wasn't my best display but what do champions do? They prevail," Buatsi commented in the ringside as he was met by negative reactions from the spectators.
The British fighter got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to secure a 20th pro success.
Some ringside observers felt the challenger, thirty-one, should have been awarded the decision but the contender suffered the second setback of his 28-fight career.
The Champion Secures Win in Dull Encounter
The fighter's advancement has plateaued in recent times through management issues and long spells of inactivity.
Earlier forecast as the next star of the British fight scene, he now is positioned trying to achieve expectations - maybe in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a tentative opening few rounds.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after breaking his hand mid-fight, was making just his second appearance at the higher weight class.
By the middle rounds, Parker had stayed in contention, making life awkward for Buatsi, who utilized a solid defense to edge the more effective periods.
The crowd's patience wore thin amid regular grabbing, with Parker slipping to the canvas several times during grappling.
Parker finished the stronger, but many rounds were difficult to score. However, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still seems difficult.
Hatton Homage Motivates Manchester Derby Fight
In the supporting bout, Arthur overcame Bradley Rea by split-decision in a outstanding local rivalry contest to win the European light heavyweight title.
The venue grew hushed for a deeply poignant memorial prior to the bout as 10 bells tolled in remembrance of Manchester's own Ricky Hatton, who died 46 years old in last month.
It was the premier televised boxing event in the city since Hatton's death. As the last bell ended, the quiet transitioned to a chant of "only one Hatton".
The competition within the ring equaled the sentiment. Arthur was knocked down by a left hook flush on the chin in the early round, rising shakily to his feet on the eight count.
But the red-colored attire of Arthur soon pressed ahead again. From the other corner, Rea - in competitive blue - was damaged soon, noticeable damage developing under his face as the fighters traded punishing blows.
Rea, 27, connected with strong blows but Arthur, thirty-four, responded in kind with effective uppercuts as the intensity seldom decreased over 12 rounds.
Arthur narrowly won the result with scoring tallies of even score, close margin and 115-112, but each competitor were relentless and brave, everything their hero Hatton represented.
