British light heavyweight Buatsi made a winning yet unimpressive debut to life under new promoters with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a majority decision in a close ten-round contest at the Co-op Live Arena.
But Parker landed significant shots, delivering effective clean blows in a fight where the approaches failed to mesh, with constant grabbing spoiling the contest.
The officials judged it 96-94 to Buatsi, with the remaining official a even score.
"It wasn't my greatest performance but what do champions do? They succeed," the victor stated in the arena as he was faced disapproval from the spectators.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in last winter - to earn a twentieth professional win.
Various analysts believed the challenger, thirty-one, merited the win but the Derbyshire fighter endured the second loss of his 28-fight professional journey.
The Champion Earns Triumph in Dull Encounter
His career development has plateaued in the past few years through contract problems and long spells of lack of fights.
Earlier forecast as the future of the British fight scene, he now is positioned trying to realize his potential - possibly in what seems like a final roll of the dice - under recent support.
He opened tentatively, with neither fighter ready to take risks in a tentative initial rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in 2022 after breaking his hand mid-fight, was making just his second fight at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, making life awkward for the favorite, who operated with a tight guard to narrowly win the cleaner periods.
The crowd's patience wore thin amid regular grabbing, with the challenger slipping to the canvas several times during grappling.
Parker finished the stronger, but multiple periods were challenging to assess. However, former world champion the boxing analyst - working with Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
Buatsi moves on, but with the presence of heavy hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still appears challenging.
Ricky Hatton Homage Inspires All-Manchester Battle
In the supporting bout, Arthur beat Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to capture 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 Manchester's own Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast boxing event in the location since the passing of Hatton. As the concluding sound faded, the stillness became a chant of "there's just one Hatton".
The competition inside the ropes equaled the feeling. Arthur was floored by a significant blow squarely on the jaw in the second round, standing uncertainly to his position on the eight count.
But the red-colored equipment of Arthur soon pressed ahead again. From the other corner, the opponent - in opposing blue - was injured soon, heavy swelling developing under his face as the pair exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over 12 rounds.
The victor narrowly won the verdict with official scores of draw, 115-113 and 115-112, but both fighters were persistent and full of heart, everything their hero the legend embodied.
