UK light-heavyweight Buatsi secured a victory yet underwhelming start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output likely gained him a majority decision in a close 10-round fight at the boxing arena.
But Parker landed significant shots, delivering effective individual punches in a fight where the approaches didn't complement each other, with frequent clinching spoiling the contest.
The scoring judges had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my best performance but what do champions do? They succeed," Buatsi commented in the arena as he was met by negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an memorable fight with his previous opponent in last winter - to earn a twentieth professional win.
Several boxing experts believed Parker, 31, should have been awarded the decision but the contender suffered the second setback of his 28-fight professional journey.
Buatsi Secures Win in Dull Affair
The fighter's advancement has plateaued in the past few years through contract problems and extended periods of lack of fights.
Previously predicted as the next star of British boxing, he now is positioned trying to realize his potential - perhaps in what seems like a final roll of the dice - under fresh management.
He opened tentatively, with the two boxers ready to overcommit in a tentative opening few rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in 2022 after breaking his hand during the bout, was competing in only his second fight at light heavyweight.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who utilized a solid defense to edge the better periods.
The spectators' acceptance wore thin amid constant clinching, with Parker slipping to the canvas several times during clinches.
The underdog closed well, but several stanzas were difficult to score. Nevertheless, ex-champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
Buatsi advances, but with the caliber of hard hitter Benavidez, and Russian star Bivol leading the category, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Homage Motivates Manchester Derby Fight
In the co-main event, Lyndon Arthur beat Bradley Rea by divided decision in a outstanding local rivalry fight to win the European light heavyweight title.
The arena fell silent for a extremely emotional homage prior to the bout as 10 bells tolled in memory of Manchester's own Ricky Hatton, who died at age 46 in recently.
It was the first major televised match card in the city since Hatton's death. As the final chime disappeared, the silence became a roar of "there's just one Ricky Hatton".
The competition inside the ropes reflected the emotion. The eventual winner was knocked down by a left hook directly to the face in the early round, rising shakily to his feet on the count of eight.
But the red-colored attire of the fighter soon advanced again. Across the ring, Rea - in opposing blue - was damaged quickly, heavy swelling appearing under his eye as the duo landed hard punches.
Rea, twenty-seven, landed power punches but the champion, 34, fought fire with fire with effective uppercuts as the intensity seldom decreased over the full distance.
The victor narrowly won the result with judges scorecards of draw, 115-113 and wider gap, but both fighters were determined and brave, all the qualities their inspiration the legend embodied.
