UK light heavyweight Buatsi secured a victory yet underwhelming debut to his career under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a majority decision in a competitive ten-round contest at the Manchester venue.
But Parker had his moments, landing some telling single shots in a fight where the approaches failed to mesh, with constant grabbing spoiling the fight.
Two judges scored it 96-94 in favor to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi said in the ring as he was greeted with disapproval from the audience.
The British fighter got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to secure a 20th career victory.
Several boxing experts felt Parker, 31, should have been awarded the victory but the contender experienced the second loss of his 28-match professional journey.
The Champion Claims Victory in Uneventful Affair
His career development has stalled in recent times through contract problems and extended periods of lack of fights.
Once tipped as the next star of UK boxing, he now stands trying to realize his potential - maybe in what appears to be a final roll of the dice - under fresh management.
He opened tentatively, with the two boxers ready to overcommit in a tentative opening few rounds.
Parker, whose single earlier setback came at super middleweight against John Ryder in 2022 after damaging his hand mid-fight, was participating in his second fight at the higher weight class.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who utilized a tight guard to narrowly win the cleaner stanzas.
The spectators' acceptance wore thin because of constant clinching, with the challenger going down multiple occasions during clinches.
Parker ended stronger, but many rounds were challenging to assess. Although, ex-champion the boxing analyst - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just one round.
The victor advances, but with the likes of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the path to championship success - on this evidence - still seems difficult.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a terrific local rivalry battle to secure the continental title.
The arena fell silent for a deeply poignant homage prior to the bout as ten bells rang in honor of the city's native Ricky Hatton, who died at age 46 in last month.
It was the premier televised match card in the location since Hatton's passing. As the concluding sound ended, the quiet became a roar of "there's only one Hatton".
The competition during the bout matched the emotion. 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 referee's count.
But the red-colored equipment of Arthur soon came forward again. On the opposite side, Rea - in competitive blue - was injured soon, heavy swelling forming under his face as the pair landed powerful shots.
The challenger, 27, connected with strong blows but the champion, thirty-four, responded in kind with powerful upward punches as the pace hardly diminished over 12 rounds.
The victor barely secured the verdict with scoring tallies of draw, close margin and wider gap, but each competitor were relentless and full of heart, everything their idol the legend embodied.
