British light heavyweight Buatsi earned a win yet underwhelming beginning to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a majority decision in a close ten-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful individual punches in a match where the styles didn't complement each other, with excessive holding disrupting the action.
The scoring judges judged it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my best display but what do champions do? They succeed," Buatsi said in the ringside as he was faced boos from the crowd.
The British fighter got back to winning after his initial pro loss - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Several boxing experts believed Parker, 31, should have been awarded the decision but the Derbyshire fighter suffered the second defeat of his 28-match career.
Buatsi Earns Triumph in Dull Encounter
Buatsi's progress has stalled in recent times through management issues and long spells of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now finds himself trying to realize his potential - possibly in what feels like a last chance - under fresh management.
He started carefully, with both competitors prepared to overcommit in a tentative opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury mid-fight, was competing in only his second appearance at light heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for Buatsi, who utilized a solid defense to narrowly win the more effective rounds.
The audience's tolerance decreased because of constant clinching, with the challenger going down various instances during clinches.
The underdog finished the stronger, but many rounds were hard to judge. However, previous titleholder the boxing analyst - working with Dazn - had it strongly leaning for the challenger, giving Buatsi just one round.
The victor progresses, but with the presence of hard hitter David Benavidez, and Russian star Bivol leading the category, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Homage Inspires All-Manchester Battle
In the secondary fight, Arthur beat Bradley Rea by close verdict in a terrific all-Manchester fight to secure the continental championship.
The stadium grew hushed for a deeply poignant tribute before the fight as 10 bells rang in honor of local hero Hatton, who succumbed aged 46 in last month.
It was the first major televised fight night in the urban center since Hatton's death. As the last bell faded, the silence became a roar of "there's just one Hatton".
The competition during the bout matched the sentiment. Arthur was floored by a left hook squarely on the face in the second round, rising shakily to his footing on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was injured quickly, heavy swelling developing under his eye as the pair traded punishing blows.
Rea, 27, connected with strong blows but Arthur, thirty-four, matched the intensity with stinging uppercuts as the pace rarely dropped over twelve rounds.
Arthur narrowly won the result with official scores of 114-114, close margin and 115-112, but both fighters were relentless and full of heart, exactly what their hero Hatton embodied.
