British light-heavyweight Buatsi secured a victory yet disappointing start to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a competitive 10-round fight at the Co-op Live Arena.
But Parker had his moments, delivering effective individual punches in a match where the styles failed to mesh, with excessive holding disrupting the contest.
The officials judged it 96-94 for to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest display but what defines champions? They prevail," Buatsi commented in the arena as he was greeted with disapproval from the spectators.
The Londoner bounced back after his initial pro loss - an thrilling contest with his previous opponent in February - to secure a 20th career victory.
Several boxing experts thought Parker, 31, merited the win but the contender experienced the second loss of his 28-bout professional journey.
The Champion Earns Victory in Dull Match
Buatsi's progress has plateaued in the past few years through contract problems and extended periods of inactivity.
Once tipped as the next star of the British fight scene, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under recent support.
He opened tentatively, with neither fighter willing to take risks in a cagey initial rounds.
Parker, whose sole prior loss came at super-middleweight against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at the higher weight class.
By the halfway stage, the underdog had kept it close, causing problems for the favorite, who worked behind a tight guard to narrowly win the better periods.
The audience's tolerance diminished amid frequent holding, with Parker going down multiple occasions during close exchanges.
Parker ended stronger, but multiple periods were difficult to score. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
The victor progresses, but with the likes of power puncher David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Homage Fuels All-Manchester Contest
In the supporting bout, Lyndon Arthur beat Bradley Rea by divided decision in a excellent Manchester vs Manchester battle to secure the European light heavyweight belt.
The venue grew hushed for a extremely emotional tribute ahead of the contest as a bell ceremony sounded in honor of the city's native Hatton, who passed away 46 years old in September.
It was the first major televised boxing event in the location since Hatton's passing. As the final chime disappeared, the silence transitioned to a roar of "only one Hatton".
The action inside the ropes reflected the feeling. Arthur was knocked down by a powerful punch squarely on the face in the initial stage, getting up unsteadily to his position on the eight count.
But the red-colored equipment of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was marked up quickly, significant bruising forming under his face as the fighters exchanged hard punches.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over 12 rounds.
Arthur edged the verdict with official scores of even score, narrow lead and wider gap, but the two athletes were determined and full of heart, everything their hero Hatton stood for.
