British light heavyweight Buatsi earned a win yet underwhelming debut to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a close 10-round fight at the boxing arena.
But the challenger landed significant shots, delivering effective individual punches in a contest where the styles failed to mesh, with constant grabbing marring the fight.
The officials had it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my finest showing but what do champions do? They win," the victor stated in the arena as he was faced boos from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a twentieth professional win.
Various analysts thought the challenger, 31, deserved the decision but the British boxer experienced the second defeat of his 28-match professional journey.
Buatsi Secures Victory in Slow Encounter
His career development has slowed in recent times through promotional disputes and long spells of inactivity.
Previously predicted as the next star of UK boxing, he now stands trying to realize his potential - maybe in what feels like a final roll of the dice - under recent support.
He started carefully, with both competitors willing to take risks in a cagey initial rounds.
Parker, whose sole prior loss came at the lower weight class against John Ryder in 2022 after breaking his hand in the contest, was competing in only his second bout at the higher weight class.
By the middle rounds, the underdog had made it competitive, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the better stanzas.
The audience's tolerance diminished during constant clinching, with Parker slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but multiple periods were challenging to assess. Nevertheless, previous titleholder Carl Frampton - working with Dazn - had it significantly in favor for Parker, giving Buatsi just one round.
Buatsi moves on, but with the likes of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a outstanding Manchester vs Manchester contest to secure the European light heavyweight title.
The venue grew hushed for a profoundly moving tribute ahead of the contest as 10 bells rang in honor of local hero Ricky Hatton, who died 46 years old in September.
It was the premier televised fight night in the location since the passing of Hatton. As the final chime faded, the stillness gave way to a chant of "there's just one Hatton".
The action inside the ropes matched the emotion. The eventual winner was floored by a left hook flush on the face in the early round, standing uncertainly to his feet on the count of eight.
But the traditional red attire of the fighter soon advanced again. Across the ring, Rea - in competitive blue - was marked up soon, significant bruising forming under his face as the fighters landed powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, responded in kind with effective uppercuts as the action hardly diminished over twelve rounds.
The victor narrowly won the decision with judges scorecards of even score, 115-113 and wider gap, but each competitor were persistent and full of heart, everything their idol Hatton represented.
