UK light-heavyweight Buatsi secured a victory yet underwhelming beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a close 10-round fight at the boxing arena.
But the challenger found success, connecting with powerful individual punches in a fight where the approaches didn't complement each other, with constant grabbing disrupting the action.
The scoring judges had it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my finest showing but how do champions respond? They win," the victor commented in the arena as he was greeted with negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an epic battle with his previous opponent in February - to earn a 20th career victory.
Some ringside observers felt the challenger, thirty-one, merited the decision but the contender suffered the second defeat of his 28-match professional journey.
Buatsi Secures Victory in Dull Match
The fighter's advancement has stalled in the past few years through management issues and extended periods of inactivity.
Earlier forecast as the future of British boxing, he now stands trying to achieve expectations - possibly in what seems like a final roll of the dice - under new promotional backing.
He opened tentatively, with the two boxers willing to overcommit in a calculated opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand during the bout, was competing in only his second bout at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a tight guard to narrowly win the cleaner periods.
The crowd's patience decreased because of constant clinching, with the challenger slipping to the canvas various instances during clinches.
Parker ended stronger, but many rounds were hard to judge. However, previous titleholder Carl Frampton - commentating on the broadcast network - had it particularly wide for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of hard hitter David Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Homage Motivates Manchester Derby Battle
In the co-main event, Lyndon Arthur defeated Rea by divided decision in a terrific local rivalry battle to win the continental championship.
The stadium fell silent for a profoundly moving tribute prior to the bout as a bell ceremony sounded in memory of local hero Ricky Hatton, who passed away 46 years old in recently.
It was the first major televised match card in the urban center since Hatton's passing. As the last bell disappeared, the silence gave way to a shout of "only one Ricky Hatton".
The competition during the bout reflected the feeling. The eventual winner was knocked down by a powerful punch flush on the jaw in the early round, standing uncertainly to his feet on the eight count.
But the traditional red shorts of the fighter soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was injured quickly, significant bruising forming under his eye as the duo exchanged hard punches.
Rea, 27, landed power punches but Arthur, 34, fought fire with fire with effective uppercuts as the intensity rarely dropped over 12 rounds.
The victor narrowly won the result with scoring tallies of even score, close margin and wider gap, but each competitor were determined and full of heart, exactly what their inspiration Hatton represented.
