British light heavyweight Buatsi made a winning yet underwhelming start to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a close ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling single shots in a match where the styles never quite clicked, with constant grabbing disrupting the contest.
Two judges had it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my best performance but what defines champions? They prevail," the victor said in the arena as he was met by boos from the crowd.
The Londoner got back to winning after his maiden career setback - an epic battle with Callum Smith in last winter - to secure a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, merited the win but the British boxer suffered the second loss of his 28-match career.
Buatsi Secures Win in Slow Encounter
His career development has plateaued in recent years through contract problems and considerable time of inactivity.
Once tipped as the next star of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what seems like a last chance - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a calculated opening few rounds.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was making just his second fight at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for the favorite, who worked behind a protective stance to barely take the better rounds.
The crowd's patience wore thin because of regular grabbing, with Parker going down multiple occasions during close exchanges.
The underdog closed well, but several stanzas were hard to judge. Nevertheless, former world champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, awarding Buatsi just one round.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Memorial Inspires Manchester Derby Battle
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a excellent local rivalry fight to win the European light heavyweight belt.
The venue became quiet for a profoundly moving tribute ahead of the contest as ten bells sounded in remembrance of local hero Ricky Hatton, who passed away at age 46 in recently.
It was the first major televised fight night in the location since the passing of Hatton. As the final chime disappeared, the silence became a roar of "only one Hatton".
The action within the ring matched the feeling. The eventual winner was floored by a left hook directly to the face in the initial stage, getting up unsteadily to his feet on the count of eight.
But the red-colored attire of Arthur soon came forward again. Across the ring, Rea - in competitive blue - was marked up quickly, heavy swelling appearing under his face as the duo traded punishing blows.
The challenger, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with effective uppercuts as the action hardly diminished over 12 rounds.
The victor edged the result with official scores of 114-114, 115-113 and wider gap, but the two athletes were relentless and full of heart, all the qualities their hero Hatton embodied.
