UK light heavyweight Buatsi secured a victory yet disappointing start to life under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a split decision in a tight 10-round fight at the Manchester venue.
But the challenger had his moments, landing some telling clean blows in a match where the styles never quite clicked, with constant grabbing disrupting the action.
The scoring judges had it 96-94 to Buatsi, with the third a 95-95 draw.
"It wasn't my finest showing but what defines champions? They prevail," Buatsi stated in the ring as he was met by negative reactions from the audience.
The Londoner returned to winning ways after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a 20th career victory.
Several boxing experts thought Parker, thirty-one, deserved the victory but the British boxer experienced the second setback of his 28-fight professional journey.
Buatsi Secures Triumph in Slow Affair
The fighter's advancement has stalled in the past few years through promotional disputes and extended periods of lack of fights.
Previously predicted as the rising talent of the British fight scene, he now stands trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers prepared to overcommit in a calculated opening few rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was making just his second appearance at the higher weight class.
By the middle rounds, the underdog had stayed in contention, making life awkward for Buatsi, who operated with a protective stance to edge the cleaner rounds.
The spectators' acceptance wore thin amid frequent holding, with Parker slipping to the canvas several times during grappling.
Parker ended stronger, but multiple periods were difficult to score. However, ex-champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, awarding Buatsi just one round.
Buatsi advances, but with the likes of hard hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - on this evidence - still looks steep.
Hatton Tribute Fuels Manchester Derby Battle
In the co-main event, Arthur beat Rea by split-decision in a outstanding all-Manchester contest to win the European light heavyweight championship.
The stadium grew hushed for a deeply poignant memorial prior to the bout as a bell ceremony sounded in honor of Manchester's own Hatton, who passed away 46 years old in recently.
It was the first major televised match card in the location since Hatton's death. As the last bell faded, the quiet gave way to a chant of "only one Ricky Hatton".
The fighting during the bout matched the sentiment. The eventual winner was knocked down by a significant blow flush on the chin in the early round, rising shakily to his position on the referee's count.
But the red-colored equipment of the fighter soon advanced again. On the opposite side, the opponent - in competitive blue - was injured quickly, heavy swelling appearing under his orbital area as the pair landed hard punches.
The challenger, twenty-seven, landed power punches but the champion, thirty-four, matched the intensity with stinging uppercuts as the intensity rarely dropped over 12 rounds.
Arthur edged the result with judges scorecards of even score, 115-113 and clearer margin, but the two athletes were persistent and full of heart, all the qualities their hero the legend stood for.
