UK light heavyweight Buatsi made a winning yet unimpressive beginning to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a split decision in a competitive 10-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful individual punches in a fight where the techniques never quite clicked, with frequent clinching disrupting the contest.
The officials scored it 96-94 in favor to Buatsi, with the third a 95-95.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi stated in the ring as he was faced boos from the audience.
The British fighter bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to earn a 20th career victory.
Some ringside observers felt Parker, 31, deserved the victory but the contender experienced the second loss of his 28-fight professional journey.
Buatsi Claims Victory in Slow Affair
Buatsi's progress has plateaued in recent times through contract problems and considerable time of lack of fights.
Previously predicted as the next star of the British fight scene, he now is positioned trying to realize his potential - perhaps in what appears to be a last chance - under fresh management.
He started carefully, with the two boxers ready to take risks in a cagey initial rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was competing in only his second appearance at the higher weight class.
By the middle rounds, the underdog had stayed in contention, creating difficulties for the favorite, who utilized a solid defense to narrowly win the more effective periods.
The spectators' acceptance diminished because of constant clinching, with Parker going down various instances during grappling.
The underdog ended stronger, but many rounds were difficult to score. Although, ex-champion the boxing analyst - working with Dazn - had it strongly leaning for Parker, scoring for Buatsi just a single round.
Buatsi progresses, but with the presence of heavy hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Tribute Motivates Manchester Derby Battle
In the supporting bout, Arthur beat Rea by split-decision in a terrific all-Manchester battle to capture the European light heavyweight belt.
The arena fell silent for a extremely emotional tribute before the fight as 10 bells tolled in memory of local hero Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's passing. As the final chime faded, the quiet transitioned to a roar of "there's just one Ricky Hatton".
The fighting during the bout equaled the feeling. The eventual winner was knocked down by a significant blow squarely on the chin in the initial stage, standing uncertainly to his feet on the referee's count.
But the Manchester United-red attire of the fighter soon came forward again. From the other corner, the opponent - in competitive blue - was damaged early, significant bruising developing under his eye as the fighters exchanged hard punches.
Rea, 27, landed power punches but the champion, 34, matched the intensity with stinging uppercuts as the pace hardly diminished over the full distance.
Arthur narrowly won the decision with judges scorecards of 114-114, close margin and clearer margin, but the two athletes were determined and brave, all the qualities their inspiration the legend stood for.
