British light heavyweight Buatsi earned a win yet underwhelming beginning to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a judges' verdict in a tight 10-round bout at the Co-op Live Arena.
But Parker had his moments, connecting with powerful single shots in a contest where the techniques failed to mesh, with frequent clinching marring the action.
The officials scored it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my greatest display but how do champions respond? They win," the victor said in the ringside as he was greeted with disapproval from the audience.
The Londoner returned to winning ways after his initial pro loss - an epic battle with his previous opponent in February - to earn a 20th career victory.
Various analysts felt the challenger, 31, deserved the decision but the Derbyshire fighter suffered the second setback of his 28-match professional journey.
Buatsi Claims Victory in Dull Match
Buatsi's progress has slowed in recent times through management issues and extended periods of lack of fights.
Once tipped as the next star of the British fight scene, he now finds himself trying to achieve expectations - maybe in what appears to be a final roll of the dice - under recent support.
He started carefully, with the two boxers ready to take risks in a tentative early stages.
Parker, whose single earlier setback came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was participating in his second fight at light-heavyweight.
By the fight's midpoint, the underdog had stayed in contention, creating difficulties for Buatsi, who operated with a tight guard to narrowly win the cleaner rounds.
The spectators' acceptance diminished because of frequent holding, with Parker slipping to the canvas various instances during grappling.
Parker closed well, but several stanzas were hard to judge. Nevertheless, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor moves on, but with the caliber of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the road to world glory - judging by this showing - still looks steep.
Ricky Hatton Memorial Inspires All-Manchester Contest
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a outstanding Manchester vs Manchester battle to secure the European light-heavyweight belt.
The arena grew hushed for a deeply poignant homage ahead of the contest as 10 bells rang in remembrance of Manchester's own Ricky Hatton, who passed away at age 46 in recently.
It was the first major televised boxing event in the urban center since the passing of Hatton. As the concluding sound disappeared, the stillness gave way to a shout of "there's only one Hatton".
The action during the bout equaled the emotion. Arthur was sent to the canvas by a powerful punch squarely on the face in the early round, standing uncertainly to his position on the referee's count.
But the traditional red shorts of the fighter soon advanced again. Across the ring, the opponent - in competitive blue - was marked up quickly, heavy swelling forming under his orbital area as the duo exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but the champion, 34, responded in kind with powerful upward punches as the intensity hardly diminished over twelve rounds.
Arthur narrowly won the result with official scores of draw, close margin and 115-112, but both fighters were persistent and courageous, exactly what their hero Hatton represented.
