UK light-heavyweight Buatsi made a winning yet underwhelming beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a split decision in a competitive ten-round contest at the boxing arena.
But Parker had his moments, connecting with powerful single shots in a match where the techniques didn't complement each other, with constant grabbing marring the action.
Two judges scored it 96-94 to the winner, with the final judge a 95-95.
"It wasn't my finest performance but what defines champions? They prevail," the victor stated in the ring as he was greeted with disapproval from the crowd.
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 career victory.
Various analysts felt Parker, thirty-one, merited the win but the British boxer suffered the second loss of his 28-bout career.
Buatsi Earns Triumph in Dull Encounter
The fighter's advancement has slowed in recent times through promotional disputes and considerable time of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to achieve expectations - maybe in what seems like a last chance - under fresh management.
He opened tentatively, with neither fighter ready to take risks in a calculated initial rounds.
Parker, whose only previous defeat came at super-middleweight against his former opponent in two years ago after breaking his hand mid-fight, was competing in only his second fight at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for the favorite, who operated with a tight guard to narrowly win the cleaner periods.
The audience's tolerance diminished amid regular grabbing, with Parker going down various instances during grappling.
Parker closed well, but multiple periods were difficult to score. Nevertheless, former world champion Carl Frampton - working with Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi progresses, but with the presence of power puncher Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Memorial Fuels Local Rivalry Fight
In the secondary fight, Arthur beat Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to secure the continental championship.
The venue became quiet for a extremely emotional tribute prior to the bout as a bell ceremony rang in honor of local hero Ricky Hatton, who died 46 years old in last month.
It was the premier televised boxing event in the city since the passing of Hatton. As the last bell disappeared, the quiet became a chant of "there's only one Ricky Hatton".
The competition within the ring matched the sentiment. Arthur was knocked down by a powerful punch squarely on the face in the early round, standing uncertainly to his footing on the eight count.
But the red-colored attire of Arthur soon pressed ahead again. From the other corner, the opponent - in rival City blue - was injured quickly, noticeable damage developing under his eye as the fighters landed powerful shots.
Rea, 27, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the action rarely dropped over 12 rounds.
Arthur narrowly won the result with official scores of draw, narrow lead and clearer margin, but the two athletes were persistent and brave, everything their idol Hatton represented.
