UK light heavyweight Buatsi secured a victory yet disappointing debut to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a tight 10-round contest at the Co-op Live Arena.
But Parker found success, landing some telling single shots in a contest where the techniques failed to mesh, with constant grabbing marring the action.
The officials judged it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest performance but what defines champions? They prevail," the victor commented in the ring as he was faced negative reactions from the crowd.
The Londoner returned to winning ways after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts thought Parker, thirty-one, deserved the win but the Derbyshire fighter suffered the second defeat of his 28-match career.
Buatsi Claims Victory in Uneventful Encounter
Buatsi's progress has plateaued in recent years through contract problems and long spells of inactivity.
Earlier forecast as the rising talent of UK boxing, he now stands trying to achieve expectations - perhaps in what appears to be a final roll of the dice - under recent support.
He opened tentatively, with the two boxers prepared to take risks in a cagey early stages.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in two years ago after breaking his hand in the contest, was competing in only his second appearance at light-heavyweight.
By the middle rounds, the underdog had made it competitive, causing problems for Buatsi, who operated with a tight guard to edge the cleaner rounds.
The audience's tolerance wore thin amid regular grabbing, with Parker going down several times during close exchanges.
Parker ended stronger, but several stanzas were hard to judge. Nevertheless, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, giving Buatsi just one round.
The victor advances, but with the caliber of power puncher David Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - on this evidence - still looks steep.
Ricky Hatton Memorial Fuels All-Manchester Contest
In the co-main event, Arthur beat Bradley Rea by divided decision in a outstanding all-Manchester fight to win the European light heavyweight championship.
The arena grew hushed for a profoundly moving tribute ahead of the contest as 10 bells tolled in memory of Manchester's own Hatton, who passed away at age 46 in last month.
It was the premier televised match card in the urban center since the passing of Hatton. As the concluding sound faded, the quiet became a chant of "there's only one Hatton".
The fighting within the ring matched the emotion. The eventual winner was floored by a powerful punch directly to the face in the early round, standing uncertainly to his feet on the eight count.
But the red-colored attire of the fighter soon advanced again. On the opposite side, Rea - in competitive blue - was marked up early, noticeable damage appearing under his face as the fighters landed punishing blows.
Rea, 27, delivered effective strikes but the champion, thirty-four, matched the intensity with effective uppercuts as the pace seldom decreased over the full distance.
The victor edged the decision with official scores of draw, 115-113 and clearer margin, but each competitor were persistent and brave, all the qualities their inspiration Hatton embodied.
