British light-heavyweight Buatsi secured a victory yet disappointing debut to life under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a split decision in a competitive 10-round fight at the Co-op Live Arena.
But Parker had his moments, connecting with powerful single shots in a fight where the approaches failed to mesh, with constant grabbing spoiling the contest.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a even score.
"It wasn't my greatest display but what defines champions? They succeed," the victor said in the ringside as he was greeted with disapproval from the crowd.
The British fighter bounced back after his first professional defeat - an epic battle with Callum Smith in February - to earn a 20th pro success.
Several boxing experts believed the challenger, 31, should have been awarded the win but the Derbyshire fighter experienced the second defeat of his 28-match career.
The Champion Earns Triumph in Slow Match
The fighter's advancement has stalled in recent times through contract problems and long spells of inactivity.
Previously predicted as the future of UK boxing, he now stands trying to fulfil that early promise - possibly in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with the two boxers prepared to be aggressive in a tentative early stages.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after breaking his hand during the bout, was making just his second fight 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 more effective rounds.
The crowd's patience wore thin amid constant clinching, with the challenger going down various instances during close exchanges.
Parker ended stronger, but many rounds were hard to judge. However, previous titleholder Carl Frampton - commentating on Dazn - had it strongly leaning for the challenger, giving Buatsi just one round.
The victor advances, but with the presence of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Hatton Tribute Inspires Local Rivalry Contest
In the co-main event, Arthur defeated Rea by split-decision in a outstanding local rivalry battle to secure the European light-heavyweight belt.
The venue became quiet for a profoundly moving homage ahead of the contest as ten bells sounded in honor of the city's native Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast boxing event in the city since the passing of Hatton. As the last bell disappeared, the stillness gave way to a shout of "there's just one Hatton".
The action during the bout reflected the feeling. Arthur was floored by a powerful punch squarely on the chin in the initial stage, standing uncertainly to his feet on the eight count.
But the red-colored equipment of Arthur soon came forward again. Across the ring, Rea - in competitive blue - was marked up quickly, heavy swelling developing under his orbital area as the pair exchanged punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with effective uppercuts as the intensity rarely dropped over 12 rounds.
The victor narrowly won the decision with judges scorecards of 114-114, narrow lead and 115-112, but each competitor were determined and courageous, all the qualities their idol Hatton embodied.
