UK light heavyweight Buatsi secured a victory yet unimpressive beginning to life under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a tight 10-round contest at the Manchester venue.
But Parker found success, landing some telling individual punches in a match where the styles failed to mesh, with excessive holding marring the fight.
Two judges judged it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but what defines champions? They succeed," Buatsi stated in the ring as he was greeted with disapproval from the audience.
The Londoner bounced back after his initial pro loss - an thrilling contest with Callum Smith in last winter - to earn a 20th career victory.
Some ringside observers thought the challenger, thirty-one, should have been awarded the win but the Derbyshire fighter endured the second setback of his 28-match professional journey.
Buatsi Secures Win in Dull Affair
Buatsi's progress has stalled in recent times through contract problems and extended periods of inactivity.
Once tipped as the rising talent of British boxing, he now finds himself trying to realize his potential - maybe in what appears to be a final roll of the dice - under new promotional backing.
He started carefully, with neither fighter prepared to take risks in a tentative initial rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in 2022 after breaking his hand mid-fight, was making just his second appearance at light-heavyweight.
By the middle rounds, Parker had made it competitive, causing problems for Buatsi, who worked behind a solid defense to narrowly win the better stanzas.
The spectators' acceptance wore thin because of constant clinching, with Parker slipping to the canvas several times during grappling.
The underdog finished the stronger, but many rounds were hard to judge. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it particularly wide for the challenger, awarding Buatsi just a single round.
Buatsi moves on, but with the presence of power puncher Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - judging by this showing - still appears challenging.
Hatton Memorial Motivates Local Rivalry Battle
In the co-main event, Lyndon Arthur beat Bradley Rea by close verdict in a terrific all-Manchester battle to capture the European light-heavyweight belt.
The arena grew hushed for a extremely emotional memorial before the fight as a bell ceremony tolled in remembrance of Manchester's own Hatton, who succumbed 46 years old in last month.
It was the premier televised fight night in the location since Hatton's death. As the concluding sound disappeared, the silence transitioned to a shout of "there's just one Ricky Hatton".
The competition within the ring equaled the emotion. Arthur was sent to the canvas by a left hook directly to the chin in the second round, standing uncertainly to his feet on the referee's count.
But the Manchester United-red attire of Arthur soon pressed ahead again. From the other corner, the opponent - in opposing blue - was damaged quickly, heavy swelling appearing under his face as the pair landed powerful shots.
The challenger, 27, connected with strong blows but the champion, thirty-four, responded in kind with stinging uppercuts as the action seldom decreased over twelve rounds.
The victor narrowly won the verdict with official scores of 114-114, narrow lead and 115-112, but both fighters were persistent and brave, all the qualities their inspiration the legend embodied.
