British light heavyweight Buatsi made a winning yet disappointing start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a competitive 10-round fight at the Co-op Live Arena.
But Parker landed significant shots, delivering effective individual punches in a match where the approaches never quite clicked, with frequent clinching disrupting the fight.
The scoring judges scored it 96-94 for to Buatsi, with the final judge a 95-95.
"It wasn't my finest showing but how do champions respond? They succeed," the victor stated in the arena as he was faced negative reactions from the crowd.
The Londoner returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in February - to claim a twentieth professional win.
Several boxing experts thought Parker, 31, merited the win but the contender experienced the second setback of his 28-fight career.
The Champion Secures Victory in Uneventful Affair
His career development has stalled in recent times through management issues and considerable time of inactivity.
Previously predicted as the rising talent of the British fight scene, he now is positioned trying to realize his potential - perhaps in what seems like a final roll of the dice - under recent support.
He opened tentatively, with both competitors prepared to be aggressive in a tentative initial rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in 2022 after suffering a hand injury in the contest, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for Buatsi, who operated with a protective stance to edge the cleaner rounds.
The audience's tolerance wore thin during constant clinching, with the challenger going down various instances during clinches.
The underdog finished the stronger, but many rounds were challenging to assess. Although, ex-champion the boxing analyst - commentating on the broadcast network - had it particularly wide for the challenger, giving Buatsi just one round.
Buatsi advances, but with the likes of power puncher David Benavidez, and Russian star Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Hatton Memorial Motivates All-Manchester Battle
In the co-main event, Arthur overcame Bradley Rea by close verdict in a outstanding local rivalry fight to secure the European light-heavyweight belt.
The stadium became quiet for a deeply poignant memorial before the fight as ten bells tolled in memory of local hero Ricky Hatton, who died 46 years old in recently.
It was the initial significant broadcast match card in the urban center since Hatton's death. As the last bell disappeared, the silence transitioned to a chant of "there's only one Hatton".
The fighting within the ring matched the sentiment. Arthur was floored by a powerful punch flush on the face in the early round, rising shakily to his position on the count of eight.
But the Manchester United-red equipment of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was marked up early, heavy swelling appearing under his eye as the pair exchanged hard punches.
The challenger, 27, landed power punches but Arthur, thirty-four, responded in kind with stinging uppercuts as the action rarely dropped over 12 rounds.
Arthur barely secured the result with official scores of draw, narrow lead and clearer margin, but both fighters were determined and full of heart, everything their hero the legend embodied.
