UK light heavyweight Buatsi secured a victory yet unimpressive debut to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a split decision in a close 10-round fight at the boxing arena.
But the challenger had his moments, delivering effective individual punches in a match where the techniques never quite clicked, with frequent clinching disrupting the contest.
Two judges scored it 96-94 for to Buatsi, with the third a 95-95 draw.
"It wasn't my greatest performance but how do champions respond? They prevail," Buatsi commented in the ring as he was faced boos from the audience.
The Londoner returned to winning ways after his first professional defeat - an epic battle with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts thought the challenger, 31, deserved the decision but the contender experienced the second loss of his 28-fight career.
Buatsi Secures Win in Dull Encounter
The fighter's advancement has slowed in the past few years through promotional disputes and considerable time of lack of fights.
Previously predicted as the rising talent of UK boxing, he now stands trying to fulfil that early promise - maybe in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter ready to overcommit in a cagey opening few rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in 2022 after breaking his hand during the bout, was competing in only his second bout at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for Buatsi, who worked behind a protective stance to barely take the cleaner periods.
The audience's tolerance wore thin because of regular grabbing, with Parker falling to the floor multiple occasions during clinches.
The underdog finished the stronger, but many rounds were difficult to score. However, previous titleholder Carl Frampton - providing analysis for Dazn - had it particularly wide for Parker, awarding Buatsi just one round.
Buatsi advances, but with the presence of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still seems difficult.
Ricky Hatton Homage Fuels Manchester Derby Battle
In the secondary fight, Lyndon Arthur beat Bradley Rea by close verdict in a excellent all-Manchester battle to secure the European light-heavyweight championship.
The stadium became quiet for a deeply poignant memorial before the fight as 10 bells sounded in remembrance of the city's native Ricky Hatton, who succumbed at age 46 in last month.
It was the initial significant broadcast fight night in the urban center since Hatton's passing. As the concluding sound ended, the silence became a roar of "there's just one Ricky Hatton".
The fighting during the bout reflected the sentiment. Arthur was knocked down by a left hook directly to the jaw in the second round, standing uncertainly to his position on the count of eight.
But the Manchester United-red attire of Arthur soon came forward again. Across the ring, Rea - in competitive blue - was marked up early, heavy swelling forming under his face as the pair landed powerful shots.
The challenger, 27, connected with strong blows but Arthur, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over 12 rounds.
Arthur narrowly won the verdict with scoring tallies of even score, close margin and 115-112, but both fighters were persistent and full of heart, exactly what their idol the legend represented.
