British light heavyweight Buatsi secured a victory yet unimpressive beginning to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a judges' verdict in a close 10-round contest at the Co-op Live Arena.
But the challenger found success, landing some telling clean blows in a match where the techniques never quite clicked, with frequent clinching spoiling the contest.
The officials had it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest display but what defines champions? They succeed," Buatsi commented in the ring as he was faced negative reactions from the audience.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers believed the challenger, thirty-one, should have been awarded the victory but the contender endured the second setback of his 28-bout career.
The Champion Secures Triumph in Slow Encounter
His career development has stalled in recent times through management issues and considerable time of inactivity.
Once tipped as the next star of UK boxing, he now finds himself trying to realize his potential - maybe in what appears to be a last chance - under fresh management.
He opened tentatively, with both competitors prepared 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 breaking his hand mid-fight, was competing in only his second bout at light heavyweight.
By the halfway stage, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a solid defense to barely take the cleaner rounds.
The spectators' acceptance wore thin because of regular grabbing, with Parker going down various instances during close exchanges.
The underdog ended stronger, but multiple periods were hard to judge. However, ex-champion Carl Frampton - working with Dazn - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of power puncher David Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Tribute Inspires Manchester Derby Contest
In the supporting bout, Lyndon Arthur defeated Bradley Rea by divided decision in a excellent local rivalry contest to capture the European light heavyweight title.
The venue became quiet for a extremely emotional memorial ahead of the contest as 10 bells rang in remembrance of the city's native Ricky Hatton, who passed away at age 46 in last month.
It was the premier televised fight night in the location since Hatton's death. As the last bell faded, the quiet transitioned to a chant of "only one Ricky Hatton".
The competition within the ring matched the feeling. The eventual winner was floored by a left hook directly to the jaw in the initial stage, rising shakily to his feet on the eight count.
But the red-colored shorts of Arthur soon came forward again. On the opposite side, the opponent - in rival City blue - was damaged early, noticeable damage appearing under his orbital area as the pair landed punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, 34, responded in kind with effective uppercuts as the intensity seldom decreased over the full distance.
Arthur barely secured the result with official scores of 114-114, narrow lead and clearer margin, but both fighters were determined and full of heart, all the qualities their idol Hatton represented.
