UK light heavyweight Buatsi made a winning yet unimpressive beginning to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a tight 10-round contest at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling clean blows in a match where the techniques failed to mesh, with constant grabbing spoiling the fight.
The officials had it 96-94 for to the winner, with the final judge a even score.
"It wasn't my finest display but what defines champions? They succeed," Buatsi said in the ring as he was faced negative reactions from the audience.
The Londoner got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to secure a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, deserved the victory but the contender endured the second defeat of his 28-bout career.
Buatsi Earns Win in Slow Match
Buatsi's progress has stalled in recent times through promotional disputes and long spells of inactivity.
Earlier forecast as the future of the British fight scene, he now finds himself trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He began cautiously, with the two boxers prepared to overcommit in a calculated early stages.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after breaking his hand in the contest, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, causing problems for the favorite, who operated with a tight guard to narrowly win the better rounds.
The crowd's patience wore thin because of regular grabbing, with Parker going down several times during close exchanges.
Parker ended stronger, but many rounds were challenging to assess. Nevertheless, previous titleholder the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
Buatsi advances, but with the likes of heavy hitter Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Motivates Manchester Derby Contest
In the supporting bout, Arthur defeated Bradley Rea by split-decision in a excellent Manchester vs Manchester contest to capture the continental belt.
The stadium became quiet for a profoundly moving homage prior to the bout as 10 bells tolled in remembrance of local hero Ricky Hatton, who died 46 years old in last month.
It was the initial significant broadcast fight night in the location since Hatton's death. As the last bell disappeared, the quiet became a shout of "only one Hatton".
The competition during the bout reflected the feeling. Arthur was sent to the canvas by a powerful punch squarely on the jaw in the second round, getting up unsteadily to his footing on the eight count.
But the red-colored equipment of Arthur soon came forward again. From the other corner, the opponent - in opposing blue - was injured soon, heavy swelling developing under his face as the pair landed powerful shots.
Rea, 27, landed power punches but the champion, 34, responded in kind with effective uppercuts as the action rarely dropped over twelve rounds.
The victor barely secured the result with scoring tallies of even score, narrow lead and 115-112, but each competitor were determined and brave, everything their inspiration Hatton embodied.
