UK light heavyweight Buatsi secured a victory yet disappointing beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a majority decision in a tight ten-round bout at the Manchester venue.
But the challenger had his moments, delivering effective single shots in a contest where the styles never quite clicked, with frequent clinching marring the contest.
The scoring judges had it 96-94 to the winner, with the final judge a even score.
"It wasn't my greatest showing but how do champions respond? They succeed," the victor said in the ringside as he was greeted with boos from the crowd.
The British fighter got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to claim a 20th pro success.
Some ringside observers thought Parker, 31, deserved the decision but the Derbyshire fighter endured the second loss of his 28-match career.
The Champion Earns Win in Dull Match
His career development has stalled in the past few years through management issues and extended periods of lack of fights.
Once tipped as the next star of British boxing, he now is positioned trying to realize his potential - maybe in what appears to be a last chance - under recent support.
He began cautiously, with neither fighter ready to be aggressive in a tentative opening few rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, creating difficulties for the favorite, who worked behind a tight guard to edge the cleaner rounds.
The audience's tolerance diminished during frequent holding, with the challenger falling to the floor several times during clinches.
Parker finished the stronger, but multiple periods were difficult to score. Although, previous titleholder the boxing analyst - working with the broadcast network - had it particularly wide for the challenger, giving Buatsi just only one stanza.
Buatsi advances, but with the caliber of hard hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - based on this performance - still looks steep.
Hatton Memorial Inspires Local Rivalry Contest
In the secondary fight, Lyndon Arthur overcame Rea by split-decision in a excellent local rivalry contest to secure the European light heavyweight championship.
The venue fell silent for a extremely emotional memorial before the fight as a bell ceremony sounded in memory of Manchester's own Hatton, who passed away 46 years old in last month.
It was the first major televised match card in the urban center since Hatton's passing. As the last bell ended, the stillness gave way to a roar of "only one Ricky Hatton".
The fighting within the ring reflected the feeling. The eventual winner was floored by a powerful punch flush on the jaw in the second round, standing uncertainly to his footing on the eight count.
But the traditional red equipment of the fighter soon pressed ahead again. On the opposite side, Rea - in competitive blue - was injured early, noticeable damage forming under his face as the fighters traded hard punches.
Rea, 27, landed power punches but Arthur, 34, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
Arthur edged the decision with official scores of draw, close margin and 115-112, but the two athletes were relentless and courageous, exactly what their hero Hatton stood for.
