British light-heavyweight Buatsi earned a win yet disappointing beginning to life under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a split decision in a competitive ten-round fight at the Co-op Live Arena.
But the challenger found success, delivering effective individual punches in a match where the styles failed to mesh, with constant grabbing disrupting the action.
Two judges judged it 96-94 to the winner, with the final judge a even score.
"It wasn't my best performance but what defines champions? They win," the victor said in the arena as he was met by boos from the crowd.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in February - to claim a 20th career victory.
Some ringside observers thought the challenger, 31, deserved the victory but the contender suffered the second defeat of his 28-fight professional journey.
The Champion Earns Win in Uneventful Match
His career development has plateaued in recent times through management issues and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now stands trying to realize his potential - perhaps in what seems like a last chance - under new promotional backing.
He opened tentatively, with the two boxers ready to overcommit in a calculated early stages.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in 2022 after breaking his hand during the bout, was participating in his second appearance at light-heavyweight.
By the middle rounds, the underdog had kept it close, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the more effective rounds.
The audience's tolerance wore thin amid constant clinching, with the challenger slipping to the canvas various instances during close exchanges.
Parker finished the stronger, but several stanzas were hard to judge. However, former world champion the boxing analyst - providing analysis for Dazn - had it particularly wide for the challenger, giving Buatsi just one round.
Buatsi advances, but with the likes of power puncher David Benavidez, and Russian star Bivol leading the category, the journey to titles - judging by this showing - still appears challenging.
Hatton Memorial Motivates Local Rivalry Battle
In the co-main event, Arthur overcame Bradley Rea by close verdict in a terrific all-Manchester contest to capture the European light heavyweight belt.
The stadium grew hushed for a extremely emotional memorial prior to the bout as ten bells rang in honor of local hero Ricky Hatton, who passed away 46 years old in September.
It was the premier televised boxing event in the urban center since Hatton's death. As the concluding sound faded, the silence became a shout of "only one Ricky Hatton".
The action during the bout reflected the sentiment. The eventual winner was knocked down by a left hook directly to the chin in the early round, rising shakily to his position on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. On the opposite side, Rea - in competitive blue - was marked up soon, heavy swelling forming under his eye as the fighters exchanged powerful shots.
The challenger, twenty-seven, landed power punches but Arthur, thirty-four, fought fire with fire with powerful upward punches as the action seldom decreased over twelve rounds.
The victor edged the decision with official scores of even score, close margin and clearer margin, but the two athletes were relentless and full of heart, all the qualities their idol Hatton represented.
