UK light heavyweight Buatsi secured a victory yet unimpressive beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a split decision in a tight ten-round contest at the Manchester venue.
But the challenger had his moments, landing some telling clean blows in a match where the styles failed to mesh, with constant grabbing disrupting the fight.
The scoring judges scored it 96-94 for to the winner, with the remaining official a 95-95.
"It wasn't my finest showing but how do champions respond? They prevail," the victor said in the arena as he was greeted with negative reactions from the crowd.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers felt the challenger, 31, deserved the decision but the contender endured the second defeat of his 28-match professional journey.
The Champion Earns Triumph in Dull Affair
Buatsi's progress has plateaued in recent times through promotional disputes and long spells of inactivity.
Previously predicted as the rising talent of UK boxing, he now is positioned trying to achieve expectations - maybe in what feels like a last chance - under new promotional backing.
He started carefully, with both competitors prepared to be aggressive in a cagey early stages.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in 2022 after breaking his hand in the contest, was participating in his second fight at light heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who worked behind a solid defense to narrowly win the cleaner periods.
The crowd's patience wore thin because of regular grabbing, with the challenger slipping to the canvas several times during clinches.
Parker finished the stronger, but several stanzas were hard to judge. Although, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
The victor progresses, but with the likes of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a outstanding local rivalry contest to secure the European light heavyweight championship.
The arena grew hushed for a extremely emotional memorial prior to the bout as 10 bells sounded in honor of the city's native Ricky Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast boxing event in the city since Hatton's death. As the final chime faded, the stillness became a roar of "there's just one Hatton".
The competition during the bout matched the sentiment. Arthur was knocked down by a powerful punch squarely on the jaw in the initial stage, rising shakily to his feet on the count of eight.
But the red-colored shorts of Arthur soon came forward again. On the opposite side, Rea - in opposing blue - was marked up early, noticeable damage forming under his face as the pair traded hard punches.
Rea, 27, delivered effective strikes but Arthur, 34, fought fire with fire with powerful upward punches as the action seldom decreased over the full distance.
Arthur edged the verdict with official scores of 114-114, narrow lead and clearer margin, but both fighters were determined and full of heart, all the qualities their idol the legend embodied.
