British light heavyweight Buatsi made a winning yet disappointing beginning to his career under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a split decision in a competitive 10-round bout at the boxing arena.
But the challenger had his moments, delivering effective single shots in a fight where the styles never quite clicked, with excessive holding marring the action.
The scoring judges had it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They prevail," Buatsi commented in the arena as he was greeted with negative reactions from the spectators.
The Londoner bounced back after his first professional defeat - an thrilling contest with Callum Smith in last winter - to secure a 20th pro success.
Some ringside observers thought the challenger, thirty-one, merited the win but the contender experienced the second loss of his 28-match professional journey.
The Champion Earns Win in Slow Encounter
His career development has slowed in recent years through contract problems and considerable time of lack of fights.
Earlier forecast as the rising talent of British boxing, he now stands trying to realize his potential - perhaps in what seems like a ultimate opportunity - under new promotional backing.
He started carefully, with neither fighter willing to be aggressive in a cagey initial rounds.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after suffering a hand injury during the bout, was participating in his second fight at light-heavyweight.
By the halfway stage, Parker had kept it close, causing problems for Buatsi, who operated with a tight guard to narrowly win the more effective rounds.
The spectators' acceptance decreased amid regular grabbing, with Parker slipping to the canvas several times during close exchanges.
Parker finished the stronger, but multiple periods were challenging to assess. Although, former world champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, giving Buatsi just one round.
Buatsi progresses, but with the presence of hard hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Homage Motivates All-Manchester Fight
In the secondary fight, Lyndon Arthur overcame Rea by divided decision in a terrific all-Manchester fight to win the continental championship.
The venue grew hushed for a extremely emotional memorial before the fight as ten bells sounded in honor of Manchester's own Ricky Hatton, who succumbed aged 46 in September.
It was the premier televised fight night in the location since the passing of Hatton. As the concluding sound ended, the stillness became a shout of "there's just one Hatton".
The competition inside the ropes matched the feeling. The eventual winner was sent to the canvas by a left hook flush on the chin in the second round, rising shakily to his feet on the count of eight.
But the Manchester United-red shorts of the fighter soon came forward again. On the opposite side, Rea - in opposing blue - was marked up soon, noticeable damage appearing under his face as the pair landed punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the pace hardly diminished over the full distance.
Arthur narrowly won the decision with judges scorecards of 114-114, narrow lead and clearer margin, but both fighters were determined and full of heart, everything their inspiration Hatton embodied.
