British light-heavyweight Buatsi earned a win yet disappointing debut to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a competitive ten-round bout at the boxing arena.
But the challenger found success, connecting with powerful individual punches in a contest where the techniques didn't complement each other, with frequent clinching spoiling the fight.
The officials scored it 96-94 for to the winner, with the third a 95-95.
"It wasn't my greatest showing but what do champions do? They win," the victor said in the arena as he was met by negative reactions from the crowd.
The Londoner got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, deserved the decision but the British boxer endured the second setback of his 28-fight career.
Buatsi Claims Triumph in Dull Match
His career development has plateaued in recent times through promotional disputes and extended periods of lack of fights.
Previously predicted as the next star of UK boxing, he now finds himself trying to fulfil that early promise - possibly in what seems like a ultimate opportunity - under recent support.
He started carefully, with the two boxers ready to be aggressive in a calculated early stages.
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 making just his second bout at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who worked behind a solid defense to edge the better periods.
The crowd's patience wore thin amid frequent holding, with the challenger slipping to the canvas multiple occasions during clinches.
Parker finished the stronger, but many rounds were hard to judge. However, ex-champion the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
The victor advances, but with the likes of hard hitter Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still looks steep.
Hatton Tribute Fuels Manchester Derby Battle
In the co-main event, Arthur beat Rea by close verdict in a excellent local rivalry contest to secure the European light heavyweight belt.
The stadium became quiet for a extremely emotional memorial prior to the bout as a bell ceremony tolled in honor of the city's native Hatton, who succumbed 46 years old in September.
It was the first major televised fight night in the city since Hatton's death. As the last bell ended, the quiet became a roar of "only one Ricky Hatton".
The action inside the ropes equaled the feeling. Arthur was floored by a significant blow squarely on the jaw in the initial stage, getting up unsteadily to his position on the eight count.
But the red-colored shorts of Arthur soon came forward again. Across the ring, the opponent - in opposing blue - was marked up soon, noticeable damage developing under his eye as the duo exchanged powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, 34, responded in kind with powerful upward punches as the intensity seldom decreased over the full distance.
The victor edged the verdict with scoring tallies of even score, 115-113 and 115-112, but each competitor were determined and brave, exactly what their inspiration Hatton stood for.
