UK light heavyweight Buatsi earned a win yet disappointing debut to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a close 10-round contest at the boxing arena.
But Parker had his moments, landing some telling individual punches in a fight where the techniques failed to mesh, with frequent clinching spoiling the fight.
The scoring judges scored it 96-94 in favor to Buatsi, with the third a 95-95.
"It wasn't my best showing but how do champions respond? They prevail," Buatsi commented in the ring as he was met by negative reactions from the audience.
The Londoner returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in last winter - to secure a twentieth professional win.
Several boxing experts believed Parker, thirty-one, should have been awarded the win but the British boxer endured the second loss of his 28-match career.
The Champion Earns Win in Uneventful Match
The fighter's advancement has plateaued in the past few years through promotional disputes and long spells of lack of fights.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to fulfil that early promise - possibly in what seems like a last chance - under recent support.
He began cautiously, with both competitors ready to take risks in a calculated initial rounds.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a protective stance to barely take the more effective stanzas.
The crowd's patience wore thin amid constant clinching, with Parker going down various instances during grappling.
Parker closed well, but many rounds were hard to judge. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
The victor advances, but with the likes of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - based on this performance - still seems difficult.
Hatton Tribute Fuels All-Manchester Fight
In the co-main event, Arthur defeated Bradley Rea by divided decision in a excellent Manchester vs Manchester contest to secure the European light-heavyweight championship.
The stadium fell silent for a extremely emotional homage before the fight as ten bells sounded in honor of the city's native Ricky Hatton, who succumbed 46 years old in last month.
It was the premier televised match card in the city since Hatton's passing. As the concluding sound faded, the stillness gave way to a chant of "there's only one Ricky Hatton".
The competition within the ring reflected the feeling. The eventual winner was sent to the canvas by a powerful punch squarely on the chin in the initial stage, rising shakily to his feet on the count of eight.
But the red-colored equipment of Arthur soon pressed ahead again. On the opposite side, Rea - in competitive blue - was injured early, significant bruising appearing under his face as the fighters landed hard punches.
The challenger, twenty-seven, landed power punches but the champion, 34, matched the intensity with powerful upward punches as the action rarely dropped over twelve rounds.
The victor barely secured the decision with scoring tallies of even score, narrow lead and 115-112, but the two athletes were persistent and brave, everything their inspiration Hatton embodied.
