UK light-heavyweight Buatsi secured a victory yet unimpressive debut to life under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a competitive ten-round fight at the Co-op Live Arena.
But the challenger had his moments, connecting with powerful individual punches in a fight where the approaches didn't complement each other, with constant grabbing spoiling the fight.
The scoring judges scored it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my greatest display but how do champions respond? They succeed," the victor stated in the arena as he was greeted with negative reactions from the spectators.
The British fighter bounced back after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers thought Parker, thirty-one, merited the win but the British boxer experienced the second defeat of his 28-fight professional journey.
Buatsi Claims Victory in Uneventful Affair
Buatsi's progress has slowed in the past few years through management issues and considerable time of inactivity.
Earlier forecast as the future of the British fight scene, he now finds himself trying to achieve expectations - maybe in what seems like a ultimate opportunity - under new promotional backing.
He opened tentatively, with both competitors ready to take risks in a cagey opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after suffering a hand injury during the bout, was making just his second fight at light heavyweight.
By the halfway stage, the underdog had made it competitive, causing problems for the favorite, who operated with a solid defense to barely take the cleaner rounds.
The spectators' acceptance wore thin during regular grabbing, with the challenger slipping to the canvas multiple occasions during clinches.
Parker ended stronger, but many rounds were hard to judge. Although, former world champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, awarding Buatsi just one round.
Buatsi progresses, but with the likes of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - on this evidence - still appears challenging.
Hatton Homage Inspires All-Manchester Fight
In the secondary fight, Arthur defeated Rea by divided decision in a terrific all-Manchester battle to win the European light-heavyweight belt.
The stadium fell silent for a extremely emotional memorial ahead of the contest as 10 bells rang in memory of Manchester's own Ricky Hatton, who died 46 years old in September.
It was the premier televised fight night in the urban center since the passing of Hatton. As the concluding sound ended, the quiet became a shout of "only one Hatton".
The action during the bout matched the feeling. The eventual winner was knocked down by a left hook squarely on the chin in the second round, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red shorts of the fighter soon came forward again. Across the ring, Rea - in rival City blue - was injured soon, noticeable damage developing under his eye as the pair landed punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, matched the intensity with stinging uppercuts as the action seldom decreased over 12 rounds.
The victor edged the decision with official scores of draw, narrow lead and 115-112, but each competitor were persistent and full of heart, everything their idol Hatton stood for.
