British light-heavyweight Buatsi earned a win yet disappointing beginning to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a competitive 10-round fight at the Co-op Live Arena.
But the challenger had his moments, landing some telling clean blows in a contest where the techniques failed to mesh, with frequent clinching disrupting the action.
The scoring judges judged it 96-94 to the winner, with the final judge a even score.
"It wasn't my greatest showing but what defines champions? They succeed," Buatsi commented in the ring as he was faced boos from the crowd.
The British fighter got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to earn a 20th pro success.
Several boxing experts thought the challenger, 31, deserved the win but the contender experienced the second loss of his 28-match career.
Buatsi Claims Win in Uneventful Encounter
Buatsi's progress has slowed in recent times through promotional disputes and long spells of inactivity.
Once tipped as the future of UK boxing, he now finds himself trying to realize his potential - possibly in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers ready to be aggressive in a calculated initial rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after breaking his hand mid-fight, was participating in his second fight at the higher weight class.
By the middle rounds, the underdog had kept it close, creating difficulties for Buatsi, who utilized a solid defense to narrowly win the cleaner rounds.
The crowd's patience wore thin because of frequent holding, with Parker falling to the floor various instances during close exchanges.
The underdog ended stronger, but multiple periods were challenging to assess. However, previous titleholder the boxing analyst - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the likes of heavy hitter David Benavidez, and Russian champion Bivol leading the category, the road to world glory - judging by this showing - still looks steep.
Hatton Homage Motivates Manchester Derby Contest
In the co-main event, Arthur overcame Rea by close verdict in a terrific local rivalry fight to secure the continental title.
The venue fell silent for a deeply poignant tribute prior to the bout as a bell ceremony sounded in honor of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the initial significant broadcast match card in the location since the passing of Hatton. As the last bell disappeared, the silence transitioned to a shout of "only one Ricky Hatton".
The competition inside the ropes matched the feeling. The eventual winner was knocked down by a powerful punch flush on the jaw in the second round, rising shakily to his feet on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. On the opposite side, Rea - in rival City blue - was damaged soon, significant bruising appearing under his orbital area as the pair exchanged punishing blows.
The challenger, 27, connected with strong blows but the champion, 34, matched the intensity with powerful upward punches as the action hardly diminished over 12 rounds.
The victor barely secured the result with scoring tallies of even score, 115-113 and wider gap, but the two athletes were relentless and brave, exactly what their inspiration Hatton embodied.
