UK light heavyweight Buatsi made a winning yet underwhelming debut to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a majority decision in a tight 10-round bout at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful individual punches in a match where the styles didn't complement each other, with constant grabbing marring the fight.
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 do champions do? They win," the victor stated in the ring as he was faced negative reactions from the crowd.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Several boxing experts felt Parker, thirty-one, deserved the decision but the British boxer experienced the second setback of his 28-match career.
The Champion Secures Victory in Slow Affair
His career development has plateaued in the past few years through management issues and considerable time of lack of fights.
Previously predicted as the future of British boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a last chance - under fresh management.
He began cautiously, with both competitors prepared to be aggressive in a cagey opening few rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was making just his second bout at light-heavyweight.
By the middle rounds, Parker had stayed in contention, causing problems for Buatsi, who worked behind a solid defense to narrowly win the better rounds.
The audience's tolerance wore thin because of frequent holding, with the challenger going down various instances during clinches.
The underdog ended stronger, but many rounds were challenging to assess. However, former world champion Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, awarding Buatsi just a single round.
Buatsi advances, but with the likes of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Tribute Inspires Local Rivalry Fight
In the co-main event, Arthur overcame Bradley Rea by split-decision in a excellent all-Manchester contest to capture the European light-heavyweight belt.
The arena fell silent for a deeply poignant tribute prior to the bout as 10 bells sounded in remembrance of Manchester's own Ricky Hatton, who passed away at age 46 in September.
It was the initial significant broadcast match card in the city since Hatton's death. As the final chime ended, the silence became a chant of "there's just one Ricky Hatton".
The fighting during the bout matched the feeling. The eventual winner was sent to the canvas by a powerful punch flush on the chin in the second round, getting up unsteadily to his feet on the eight count.
But the traditional red shorts of the fighter soon advanced again. Across the ring, the opponent - in competitive blue - was marked up quickly, heavy swelling developing under his orbital area as the fighters traded powerful shots.
The challenger, 27, connected with strong blows but the champion, 34, responded in kind with stinging uppercuts as the intensity seldom decreased over the full distance.
The victor narrowly won the decision with judges scorecards of even score, close margin and wider gap, but each competitor were persistent and brave, all the qualities their hero the legend represented.
