UK light-heavyweight Buatsi made a winning yet underwhelming beginning to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a split decision in a competitive ten-round fight at the boxing arena.
But Parker found success, delivering effective single shots in a contest where the styles didn't complement each other, with frequent clinching marring the action.
The scoring judges judged it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my best display but what defines champions? They prevail," Buatsi stated in the arena as he was greeted with disapproval from the spectators.
The Londoner returned to winning ways after his initial pro loss - an epic battle with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts felt Parker, thirty-one, should have been awarded the win but the British boxer experienced the second setback of his 28-match career.
Buatsi Earns Win in Uneventful Affair
Buatsi's progress has slowed in recent years through management issues and considerable time of inactivity.
Once tipped as the future of UK boxing, he now stands trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with neither fighter prepared to take risks in a tentative opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in 2022 after suffering a hand injury during the bout, was competing in only his second fight at the higher weight class.
By the halfway stage, the underdog had kept it close, making life awkward for the favorite, who operated with a tight guard to barely take the better periods.
The audience's tolerance diminished because of regular grabbing, with the challenger going down multiple occasions during grappling.
The underdog finished the stronger, but several stanzas were challenging to assess. Although, former world champion Carl Frampton - commentating on Dazn - had it particularly wide for Parker, giving Buatsi just one round.
The victor moves on, but with the likes of hard hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still looks steep.
Hatton Tribute Inspires Manchester Derby Battle
In the secondary fight, Arthur defeated Rea by close verdict in a outstanding all-Manchester battle to secure the European light-heavyweight championship.
The arena grew hushed for a deeply poignant memorial ahead of the contest as ten bells rang in honor of local hero Hatton, who died aged 46 in September.
It was the initial significant broadcast match card in the city since Hatton's passing. As the final chime ended, the stillness gave way to a chant of "there's only one Hatton".
The competition inside the ropes equaled the emotion. Arthur was knocked down by a powerful punch directly to the jaw in the early round, rising shakily to his position on the eight count.
But the traditional red equipment of Arthur soon came forward again. From the other corner, Rea - in competitive blue - was injured soon, significant bruising developing under his eye as the duo traded hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the pace hardly diminished over 12 rounds.
Arthur narrowly won the result with judges scorecards of even score, close margin and clearer margin, but both fighters were persistent and brave, all the qualities their idol Hatton embodied.
