UK light-heavyweight Buatsi secured a victory yet unimpressive start to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a split decision in a competitive ten-round fight at the boxing arena.
But Parker had his moments, connecting with powerful single shots in a fight where the approaches failed to mesh, with excessive holding disrupting the contest.
The scoring judges scored it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my greatest showing but what do champions do? They prevail," the victor said in the ring as he was met by negative reactions from the spectators.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Some ringside observers thought Parker, 31, deserved the decision but the Derbyshire fighter suffered the second loss of his 28-bout professional journey.
Buatsi Earns Win in Slow Affair
His career development has plateaued in the past few years through management issues and long spells of lack of fights.
Earlier forecast as the future of UK boxing, he now is positioned trying to realize his potential - perhaps in what feels like a last chance - under fresh management.
He began cautiously, with neither fighter ready to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was participating in his second bout at the higher weight class.
By the middle rounds, the underdog had made it competitive, creating difficulties for the favorite, who operated with a solid defense to barely take the better stanzas.
The audience's tolerance wore thin because of regular grabbing, with the challenger going down several times during close exchanges.
The underdog finished the stronger, but many rounds were difficult to score. Nevertheless, ex-champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just only one stanza.
The victor advances, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the secondary fight, Lyndon Arthur beat Rea by close verdict in a excellent all-Manchester fight to secure the European light-heavyweight title.
The arena became quiet for a deeply poignant tribute prior to the bout as a bell ceremony sounded in honor of Manchester's own Ricky Hatton, who succumbed at age 46 in September.
It was the premier televised match card in the urban center since Hatton's passing. As the concluding sound ended, the stillness gave way to a chant of "there's just one Ricky Hatton".
The fighting during the bout reflected the sentiment. The eventual winner was floored by a significant blow directly to the chin in the second round, getting up unsteadily to his footing on the count of eight.
But the red-colored shorts of the fighter soon advanced again. Across the ring, Rea - in opposing blue - was marked up early, heavy swelling forming under his face as the pair exchanged powerful shots.
Rea, 27, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the action rarely dropped over 12 rounds.
The victor narrowly won the verdict with judges scorecards of 114-114, narrow lead and 115-112, but both fighters were relentless and full of heart, exactly what their idol the legend represented.
