UK light-heavyweight Buatsi made a winning yet underwhelming beginning to his career under recent management with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a competitive 10-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful single shots in a contest where the approaches never quite clicked, with frequent clinching marring the fight.
The officials scored it 96-94 to Buatsi, with the third a 95-95 draw.
"It wasn't my best display but what do champions do? They win," the victor said in the ringside as he was met by negative reactions from the audience.
The British fighter returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to secure a 20th career victory.
Some ringside observers felt Parker, thirty-one, merited the victory but the British boxer endured the second loss of his 28-fight career.
Buatsi Earns Win in Slow Affair
The fighter's advancement has stalled in the past few years through promotional disputes and considerable time of inactivity.
Earlier forecast as the next star of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter prepared to take risks in a cagey early stages.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand in the contest, was participating in his second appearance at light-heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who operated with a protective stance to barely take the cleaner periods.
The spectators' acceptance diminished during frequent holding, with the challenger falling to the floor several times during grappling.
The underdog ended stronger, but several stanzas were challenging to assess. Nevertheless, former world champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
Buatsi advances, but with the presence of heavy hitter David Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still looks steep.
Ricky Hatton Memorial Inspires Manchester Derby Contest
In the supporting bout, Lyndon Arthur defeated Rea by close verdict in a excellent all-Manchester battle to win the continental belt.
The stadium became quiet for a extremely emotional memorial before the fight as a bell ceremony sounded in memory of Manchester's own Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's death. As the concluding sound ended, the stillness became a roar of "only one Ricky Hatton".
The fighting during the bout equaled the emotion. The eventual winner was sent to the canvas by a left hook squarely on the face in the early round, standing uncertainly to his footing on the referee's count.
But the Manchester United-red equipment of Arthur soon advanced again. On the opposite side, Rea - in competitive blue - was damaged quickly, heavy swelling appearing under his orbital area as the duo exchanged powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, responded in kind with effective uppercuts as the pace seldom decreased over 12 rounds.
The victor barely secured the decision with judges scorecards of draw, close margin and clearer margin, but both fighters were determined and courageous, everything their hero the legend embodied.
