British light heavyweight Buatsi earned a win yet unimpressive beginning to life under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a close ten-round bout at the boxing arena.
But the challenger had his moments, delivering effective individual punches in a match where the approaches didn't complement each other, with frequent clinching marring the contest.
The officials scored it 96-94 in favor to Buatsi, with the third a 95-95.
"It wasn't my finest display but what defines champions? They prevail," Buatsi commented in the arena as he was met by boos from the audience.
The British fighter bounced back after his first professional defeat - an thrilling contest with Callum Smith in February - to earn a 20th pro success.
Several boxing experts believed Parker, thirty-one, should have been awarded the decision but the contender experienced the second defeat of his 28-fight career.
His career development has slowed in recent years through contract problems and considerable time of inactivity.
Once tipped as the future of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under new promotional backing.
He opened tentatively, with both competitors willing to take risks in a tentative initial rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second appearance at light heavyweight.
By the middle rounds, the underdog had kept it close, causing problems for Buatsi, who operated with a tight guard to narrowly win the better periods.
The spectators' acceptance wore thin because of constant clinching, with the challenger falling to the floor multiple occasions during close exchanges.
The underdog ended stronger, but several stanzas were challenging to assess. Although, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for the challenger, scoring for Buatsi just only one stanza.
The victor progresses, but with the presence of heavy hitter David Benavidez, and Russian star Bivol leading the category, the journey to titles - on this evidence - still looks steep.
In the co-main event, Arthur defeated Rea by close verdict in a terrific all-Manchester contest to win the continental belt.
The stadium grew hushed for a deeply poignant memorial before the fight as ten bells rang in honor of local hero Ricky Hatton, who succumbed aged 46 in recently.
It was the premier televised match card in the city since Hatton's death. As the last bell disappeared, the stillness gave way to a chant of "there's just one Hatton".
The fighting within the ring equaled the emotion. The eventual winner was floored by a left hook flush on the chin in the second round, getting up unsteadily to his position on the referee's count.
But the Manchester United-red shorts of Arthur soon came forward again. On the opposite side, Rea - in competitive blue - was injured soon, significant bruising forming under his orbital area as the duo exchanged punishing blows.
Rea, 27, landed power punches but the champion, thirty-four, matched the intensity with effective uppercuts as the pace seldom decreased over twelve rounds.
The victor edged the decision with official scores of draw, 115-113 and clearer margin, but each competitor were relentless and brave, everything their idol Hatton represented.
