UK light heavyweight Buatsi earned a win yet underwhelming beginning to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a split decision in a close ten-round fight at the boxing arena.
But Parker landed significant shots, connecting with powerful individual punches in a match where the approaches failed to mesh, with excessive holding disrupting the fight.
The officials had it 96-94 in favor to Buatsi, with the third a even score.
"It wasn't my finest performance but how do champions respond? They win," Buatsi commented in the arena as he was greeted with negative reactions from the crowd.
The Londoner returned to winning ways after his initial pro loss - an epic battle with his previous opponent in February - to claim a 20th pro success.
Various analysts felt the challenger, thirty-one, merited the decision but the contender suffered the second loss of his 28-fight professional journey.
Buatsi Earns Triumph in Uneventful Match
Buatsi's progress has slowed in recent times through promotional disputes and long spells of lack of fights.
Once tipped as the next star of the British fight scene, he now stands trying to fulfil that early promise - perhaps in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with neither fighter willing to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in 2022 after suffering a hand injury in the contest, was making just his second fight at the higher weight class.
By the middle rounds, the underdog had stayed in contention, making life awkward for Buatsi, who worked behind a protective stance to edge the better stanzas.
The spectators' acceptance wore thin during regular grabbing, with the challenger slipping to the canvas multiple occasions during clinches.
The underdog finished the stronger, but multiple periods were challenging to assess. However, former world champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, scoring for Buatsi just one round.
The victor advances, but with the likes of power puncher Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates All-Manchester Battle
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding Manchester vs Manchester contest to win the European light heavyweight championship.
The stadium grew hushed for a extremely emotional tribute prior to the bout as ten bells tolled in honor of local hero Hatton, who died 46 years old in last month.
It was the first major televised fight night in the location since the passing of Hatton. As the last bell ended, the quiet gave way to a chant of "there's just one Ricky Hatton".
The fighting within the ring matched the feeling. The eventual winner was floored by a powerful punch directly to the jaw in the initial stage, standing uncertainly to his feet on the count of eight.
But the red-colored shorts of the fighter soon advanced again. From the other corner, the opponent - in rival City blue - was damaged quickly, heavy swelling appearing under his face as the fighters traded hard punches.
Rea, twenty-seven, delivered effective strikes but the champion, 34, matched the intensity with stinging uppercuts as the action hardly diminished over the full distance.
Arthur barely secured the decision with judges scorecards of draw, close margin and 115-112, but both fighters were persistent and courageous, everything their hero the legend stood for.
