UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a split decision in a close 10-round contest at the boxing arena.
But the challenger had his moments, landing some telling single shots in a contest where the styles didn't complement each other, with excessive holding marring the contest.
The officials had it 96-94 to the winner, with the final judge a even score.
"It wasn't my finest performance but what do champions do? They win," Buatsi commented in the arena as he was greeted with disapproval from the spectators.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Several boxing experts thought the challenger, thirty-one, should have been awarded the victory but the contender suffered the second defeat of his 28-match career.
Buatsi Earns Win in Uneventful Encounter
The fighter's advancement has slowed in the past few years through contract problems and extended periods of inactivity.
Once tipped as the future of UK boxing, he now stands trying to achieve expectations - maybe in what feels like a ultimate opportunity - under fresh management.
He began cautiously, with both competitors prepared to be aggressive in a calculated initial rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was participating in his second appearance at light heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for the favorite, who utilized a tight guard to narrowly win the better rounds.
The audience's tolerance wore thin because of frequent holding, with Parker falling to the floor various instances during close exchanges.
Parker ended stronger, but multiple periods were challenging to assess. However, former world champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, awarding Buatsi just one round.
The victor advances, but with the presence of heavy hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - on this evidence - still appears challenging.
Hatton Memorial Fuels Local Rivalry Contest
In the secondary fight, Arthur overcame Rea by split-decision in a terrific Manchester vs Manchester contest to win the European light-heavyweight title.
The arena fell silent for a extremely emotional tribute ahead of the contest as a bell ceremony sounded in memory of the city's native Ricky Hatton, who succumbed 46 years old in recently.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the final chime ended, the quiet gave way to a chant of "only one Hatton".
The fighting during the bout matched the feeling. Arthur was sent to the canvas by a significant blow squarely on the jaw in the early round, getting up unsteadily to his footing on the eight count.
But the red-colored equipment of the fighter soon pressed ahead again. On the opposite side, Rea - in rival City blue - was marked up early, heavy swelling appearing under his face as the fighters exchanged hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, matched the intensity with powerful upward punches as the action seldom decreased over 12 rounds.
The victor barely secured the verdict with scoring tallies of draw, close margin and wider gap, but both fighters were relentless and brave, all the qualities their idol Hatton represented.
