British light heavyweight Buatsi made a winning yet disappointing debut to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a tight ten-round fight at the boxing arena.
But the challenger found success, landing some telling single shots in a fight where the techniques didn't complement each other, with frequent clinching disrupting the contest.
The officials scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my greatest showing but what defines champions? They win," the victor said in the ringside as he was greeted with boos from the spectators.
The Londoner returned to winning ways after his initial pro loss - an epic battle with Callum Smith in last winter - to claim a 20th career victory.
Several boxing experts believed the challenger, thirty-one, should have been awarded the victory but the Derbyshire fighter experienced the second loss of his 28-bout professional journey.
Buatsi Secures Victory in Slow Encounter
The fighter's advancement has slowed in recent years through promotional disputes and long spells of inactivity.
Once tipped as the future of British boxing, he now stands trying to realize his potential - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with the two boxers willing to be aggressive in a cagey early stages.
Parker, whose sole prior loss came at super-middleweight 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 stayed in contention, causing problems for the favorite, who worked behind a solid defense to edge the more effective rounds.
The spectators' acceptance diminished during constant clinching, with Parker falling to the floor several times during close exchanges.
The underdog finished the stronger, but several stanzas were hard to judge. Although, ex-champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for the challenger, scoring for Buatsi just one round.
The victor advances, but with the likes of heavy hitter Benavidez, and Russian star Bivol dominating the weight class, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Tribute Inspires Local Rivalry Fight
In the supporting bout, Arthur overcame Bradley Rea by close verdict in a outstanding local rivalry contest to secure the European light-heavyweight championship.
The arena fell silent for a profoundly moving homage prior to the bout as ten bells sounded in honor of local hero Ricky Hatton, who died 46 years old in recently.
It was the initial significant broadcast match card in the location since Hatton's death. As the concluding sound faded, the stillness transitioned to a roar of "only one Hatton".
The competition within the ring matched the feeling. The eventual winner was knocked down by a left hook squarely on the face in the second round, standing uncertainly to his footing on the referee's count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. Across the ring, the opponent - in opposing blue - was injured soon, noticeable damage forming under his face as the fighters traded hard punches.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, responded in kind with effective uppercuts as the intensity hardly diminished over the full distance.
Arthur barely secured the verdict with scoring tallies of even score, close margin and clearer margin, but both fighters were determined and brave, exactly what their idol the legend embodied.
