UK light-heavyweight Buatsi earned a win yet underwhelming beginning to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a judges' verdict in a tight ten-round contest at the boxing arena.
But the challenger landed significant shots, connecting with powerful individual punches in a fight where the styles didn't complement each other, with frequent clinching disrupting the action.
The scoring judges judged it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my greatest performance but how do champions respond? They win," Buatsi stated in the ringside as he was greeted with negative reactions from the spectators.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in February - to claim a twentieth professional win.
Various analysts believed Parker, 31, deserved the win but the contender suffered the second defeat of his 28-bout professional journey.
Buatsi Claims Win in Slow Encounter
Buatsi's progress has plateaued in recent times through contract problems and considerable time of inactivity.
Earlier forecast as the next star of the British fight scene, he now finds himself trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under new promotional backing.
He started carefully, with both competitors willing to take risks in a calculated opening few rounds.
The challenger, whose sole prior loss came at super middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was competing in only his second bout at light heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who operated with a protective stance to edge the better stanzas.
The crowd's patience wore thin during regular grabbing, with the challenger going down multiple occasions during clinches.
Parker ended stronger, but many rounds were hard to judge. However, previous titleholder the boxing analyst - working with Dazn - had it significantly in favor for the challenger, awarding Buatsi just one round.
The victor moves on, but with the presence of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Homage Inspires All-Manchester Contest
In the co-main event, Arthur beat Bradley Rea by close verdict in a terrific local rivalry fight to capture the continental belt.
The stadium fell silent for a deeply poignant tribute before the fight as 10 bells rang in memory of local hero Hatton, who passed away at age 46 in recently.
It was the initial significant broadcast match card in the location since Hatton's passing. As the final chime faded, the silence gave way to a chant of "only one Hatton".
The action within the ring equaled the feeling. The eventual winner was floored by a significant blow directly to the jaw in the initial stage, standing uncertainly to his footing on the count of eight.
But the Manchester United-red shorts of the fighter soon came forward again. Across the ring, Rea - in competitive blue - was damaged soon, heavy swelling forming under his eye as the pair exchanged powerful shots.
The challenger, 27, delivered effective strikes but the champion, 34, fought fire with fire with effective uppercuts as the action rarely dropped over 12 rounds.
The victor edged the decision with official scores of 114-114, 115-113 and 115-112, but both fighters were determined and brave, exactly what their idol Hatton embodied.
