UK light-heavyweight Buatsi earned a win yet unimpressive beginning to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a judges' verdict in a competitive 10-round contest at the boxing arena.
But the challenger landed significant shots, landing some telling individual punches in a fight where the approaches failed to mesh, with excessive holding disrupting the action.
Two judges had it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi said in the ring as he was greeted with negative reactions from the audience.
The Londoner got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to earn a 20th pro success.
Various analysts thought Parker, 31, merited the decision but the Derbyshire fighter endured the second defeat of his 28-bout professional journey.
Buatsi Earns Win in Dull Encounter
The fighter's advancement has plateaued in recent times through contract problems and long spells of lack of fights.
Once tipped as the rising talent of UK boxing, he now stands trying to realize his potential - possibly in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with the two boxers willing to overcommit in a cagey early stages.
The challenger, whose single earlier setback came at super middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had made it competitive, making life awkward for Buatsi, who operated with a tight guard to barely take the better periods.
The crowd's patience diminished amid constant clinching, with the challenger going down several times during clinches.
Parker ended stronger, but multiple periods were challenging to assess. However, former world champion Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor progresses, but with the likes of heavy hitter Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - based on this performance - still seems difficult.
Hatton Tribute Inspires Manchester Derby Battle
In the secondary fight, Arthur beat Bradley Rea by close verdict in a terrific Manchester vs Manchester contest to capture the European light-heavyweight title.
The stadium fell silent for a profoundly moving memorial before the fight as ten bells tolled in memory of local hero Hatton, who succumbed aged 46 in recently.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the stillness gave way to a shout of "there's just one Hatton".
The competition inside the ropes reflected the sentiment. The eventual winner was floored by a significant blow directly to the chin in the early round, getting up unsteadily to his feet on the referee's count.
But the traditional red equipment of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was injured quickly, significant bruising developing under his orbital area as the pair traded hard punches.
The challenger, 27, delivered effective strikes but the champion, thirty-four, matched the intensity with stinging uppercuts as the pace rarely dropped over twelve rounds.
Arthur edged the decision with judges scorecards of 114-114, 115-113 and wider gap, but each competitor were relentless and brave, exactly what their idol the legend embodied.
