British light heavyweight Buatsi made a winning yet unimpressive start to his career under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a competitive 10-round contest at the Co-op Live Arena.
But the challenger found success, delivering effective individual punches in a fight where the approaches didn't complement each other, with constant grabbing marring the contest.
Two judges scored it 96-94 for to Buatsi, with the third a even score.
"It wasn't my finest performance but what defines champions? They win," the victor stated in the ring as he was met by negative reactions from the spectators.
The Londoner got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to claim a 20th pro success.
Several boxing experts believed the challenger, thirty-one, merited the victory but the contender experienced the second loss of his 28-fight career.
The Champion Secures Triumph in Slow Encounter
His career development has plateaued in recent years through management issues and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now finds himself trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with both competitors prepared to take risks in a cagey opening few rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after suffering a hand injury during the bout, was competing in only his second bout at light-heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for the favorite, who utilized a solid defense to barely take the more effective periods.
The spectators' acceptance diminished during constant clinching, with the challenger going down several times during clinches.
Parker ended stronger, but multiple periods were difficult to score. Although, former world champion the boxing analyst - commentating on Dazn - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
The victor advances, but with the presence of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Hatton Tribute Inspires All-Manchester Contest
In the supporting bout, Lyndon Arthur beat Rea by divided decision in a terrific local rivalry contest to win the European light-heavyweight championship.
The venue became quiet for a deeply poignant tribute before the fight as ten bells sounded in honor of Manchester's own Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast fight night in the location since Hatton's death. As the final chime disappeared, the stillness became a roar of "there's just one Hatton".
The action during the bout matched the sentiment. Arthur was knocked down by a powerful punch flush on the chin in the second round, rising shakily to his feet on the referee's count.
But the traditional red equipment of Arthur soon advanced again. On the opposite side, the opponent - in competitive blue - was damaged quickly, noticeable damage appearing under his eye as the fighters traded powerful shots.
Rea, 27, delivered effective strikes but Arthur, thirty-four, responded in kind with stinging uppercuts as the intensity hardly diminished over 12 rounds.
Arthur narrowly won the decision with judges scorecards of even score, narrow lead and wider gap, but each competitor were relentless and courageous, everything their hero Hatton represented.
