UK light heavyweight Buatsi secured a victory yet unimpressive start to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a split decision in a tight ten-round bout at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a fight where the approaches never quite clicked, with constant grabbing marring the contest.
Two judges scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi commented in the ring as he was met by disapproval from the spectators.
The British fighter got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a twentieth professional win.
Some ringside observers believed Parker, thirty-one, merited the decision but the Derbyshire fighter experienced the second loss of his 28-bout career.
The Champion Claims Win in Dull Affair
His career development has slowed in the past few years through contract problems and considerable time of lack of fights.
Once tipped as the rising talent of British boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under recent support.
He began cautiously, with both competitors prepared to overcommit in a tentative initial rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second appearance at the higher weight class.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who utilized a protective stance to edge the cleaner rounds.
The crowd's patience diminished amid regular grabbing, with Parker going down various instances during clinches.
The underdog ended stronger, but several stanzas were challenging to assess. Nevertheless, ex-champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the secondary fight, Arthur beat Bradley Rea by close verdict in a excellent all-Manchester contest to capture the continental title.
The arena grew hushed for a deeply poignant tribute before the fight as 10 bells tolled in honor of local hero Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised fight night in the location since Hatton's passing. As the concluding sound ended, the stillness became a chant of "only one Hatton".
The fighting inside the ropes reflected the emotion. Arthur was sent to the canvas by a left hook directly to the face in the early round, rising shakily to his position on the referee's count.
But the Manchester United-red attire of Arthur soon came forward again. On the opposite side, the opponent - in competitive blue - was damaged quickly, significant bruising developing under his face as the pair traded hard punches.
Rea, 27, landed power punches but Arthur, thirty-four, responded in kind with stinging uppercuts as the action seldom decreased over 12 rounds.
Arthur edged the verdict with official scores of 114-114, close margin and clearer margin, but both fighters were determined and brave, all the qualities their idol Hatton stood for.
