UK light-heavyweight Buatsi earned a win yet underwhelming beginning to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a split decision in a close ten-round fight at the boxing arena.
But the challenger landed significant shots, connecting with powerful clean blows in a match where the approaches never quite clicked, with constant grabbing disrupting the contest.
Two judges judged it 96-94 to the winner, with the remaining official a even score.
"It wasn't my finest performance but what do champions do? They win," the victor said in the ring as he was greeted with negative reactions from the crowd.
The British fighter bounced back after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Some ringside observers felt the challenger, thirty-one, deserved the decision but the Derbyshire fighter experienced the second setback of his 28-fight career.
The Champion Earns Win in Dull Match
Buatsi's progress has plateaued in the past few years through promotional disputes and extended periods of inactivity.
Earlier forecast as the rising talent of UK boxing, he now stands trying to realize his potential - possibly in what feels like a last chance - under fresh management.
He began cautiously, with neither fighter willing to overcommit in a cagey opening few rounds.
The challenger, whose single earlier setback came at super middleweight against John Ryder in two years ago after damaging his hand during the bout, was participating in his second appearance at light heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who operated with a solid defense to edge the cleaner rounds.
The crowd's patience wore thin amid frequent holding, with the challenger slipping to the canvas several times during grappling.
Parker closed well, but many rounds were challenging to assess. Nevertheless, ex-champion the boxing analyst - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just one round.
The victor progresses, but with the caliber of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - based on this performance - still looks steep.
Hatton Memorial Motivates Manchester Derby Contest
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a terrific local rivalry contest to secure the European light heavyweight championship.
The venue fell silent for a profoundly moving homage before the fight as a bell ceremony rang in remembrance of Manchester's own Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised fight night in the urban center since Hatton's death. As the final chime ended, the stillness gave way to a shout of "there's just one Ricky Hatton".
The fighting inside the ropes reflected the sentiment. The eventual winner was floored by a left hook directly to the face in the early round, getting up unsteadily to his position on the referee's count.
But the traditional red attire of Arthur soon pressed ahead again. From the other corner, the opponent - in competitive blue - was marked up quickly, heavy swelling developing under his orbital area as the fighters traded punishing blows.
The challenger, 27, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the pace rarely dropped over twelve rounds.
Arthur narrowly won the decision with scoring tallies of draw, narrow lead and 115-112, but the two athletes were determined and brave, all the qualities their inspiration the legend represented.
