UK light-heavyweight Buatsi earned a win yet unimpressive debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a split decision in a competitive 10-round fight at the Manchester venue.
But the challenger landed significant shots, landing some telling individual punches in a match where the techniques failed to mesh, with constant grabbing marring the fight.
Two judges had it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my best showing but what do champions do? They win," Buatsi said in the ringside as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an epic battle with his previous opponent in February - to claim a 20th career victory.
Various analysts felt the challenger, thirty-one, merited the victory but the Derbyshire fighter suffered the second loss of his 28-bout career.
Buatsi Claims Victory in Uneventful Match
The fighter's advancement has stalled in the past few years through promotional disputes and considerable time of inactivity.
Once tipped as the next star of UK boxing, he now stands trying to realize his potential - possibly in what feels like a last chance - under recent support.
He opened tentatively, with both competitors willing to take risks in a tentative initial 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 appearance at the higher weight class.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for Buatsi, who worked behind a protective stance to narrowly win the better periods.
The audience's tolerance diminished during frequent holding, with the challenger going down several times during grappling.
Parker ended stronger, but multiple periods were challenging to assess. However, former world champion Carl Frampton - working with Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
The victor moves on, but with the caliber of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Memorial Inspires Manchester Derby Fight
In the secondary fight, Arthur defeated Rea by split-decision in a outstanding local rivalry contest to secure the European light-heavyweight championship.
The arena became quiet for a deeply poignant tribute before the fight as a bell ceremony sounded in memory of the city's native Hatton, who passed away at age 46 in recently.
It was the first major televised match card in the location since the passing of Hatton. As the concluding sound ended, the stillness became a chant of "only one Hatton".
The fighting during the bout reflected the emotion. The eventual winner was floored by a left hook flush on the face in the early round, rising shakily to his footing on the eight count.
But the Manchester United-red shorts of Arthur soon advanced again. Across the ring, Rea - in opposing blue - was damaged soon, heavy swelling forming under his orbital area as the duo landed hard punches.
Rea, 27, delivered effective strikes but the champion, 34, responded in kind with stinging uppercuts as the pace seldom decreased over the full distance.
Arthur narrowly won the result with scoring tallies of 114-114, close margin and clearer margin, but each competitor were persistent and courageous, everything their idol Hatton embodied.
