UK light heavyweight Buatsi earned a win yet underwhelming start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a close ten-round bout at the Manchester venue.
But Parker found success, delivering effective clean blows in a match where the styles didn't complement each other, with excessive holding marring the contest.
The officials scored it 96-94 to the winner, with the final judge a even score.
"It wasn't my finest display but how do champions respond? They win," the victor commented in the ring as he was greeted with negative reactions from the crowd.
The British fighter returned to winning ways after his first professional defeat - an memorable fight with Callum Smith in last winter - to earn a twentieth professional win.
Various analysts believed Parker, 31, deserved the victory but the British boxer experienced the second setback of his 28-bout professional journey.
The Champion Secures Victory in Slow Affair
His career development has plateaued in recent years through contract problems and long spells of inactivity.
Previously predicted as the next star of the British fight scene, he now stands trying to realize his potential - perhaps in what feels like a final roll of the dice - under recent support.
He began cautiously, with both competitors ready to be aggressive in a tentative early stages.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in 2022 after damaging his hand during the bout, was competing in only his second appearance at light-heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for the favorite, who operated with a tight guard to narrowly win the more effective periods.
The spectators' acceptance diminished amid frequent holding, with Parker falling to the floor various instances during clinches.
The underdog ended stronger, but several stanzas were difficult to score. Nevertheless, ex-champion the boxing analyst - providing analysis for Dazn - had it strongly leaning for Parker, scoring for Buatsi just one round.
The victor advances, but with the caliber of power puncher Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates Local Rivalry Contest
In the co-main event, Lyndon Arthur defeated Rea by split-decision in a outstanding local rivalry battle to secure the European light-heavyweight title.
The arena became quiet for a extremely emotional homage ahead of the contest as 10 bells rang in honor of the city's native Hatton, who passed away 46 years old in recently.
It was the premier televised fight night in the location since Hatton's passing. As the final chime ended, the quiet became a shout of "only one Ricky Hatton".
The fighting within the ring equaled the emotion. The eventual winner was sent to the canvas by a powerful punch directly to the chin in the second round, standing uncertainly to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon came forward again. From the other corner, the opponent - in opposing blue - was marked up early, heavy swelling developing under his orbital area as the fighters exchanged powerful shots.
The challenger, 27, connected with strong blows but Arthur, 34, fought fire with fire with effective uppercuts as the intensity hardly diminished over twelve rounds.
Arthur edged the decision with official scores of 114-114, close margin and 115-112, but each competitor were relentless and brave, all the qualities their hero the legend stood for.
