UK light heavyweight Buatsi secured a victory yet disappointing start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a split decision in a competitive 10-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful single shots in a match where the techniques didn't complement each other, with excessive holding spoiling the contest.
The scoring judges judged it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my greatest showing but what do champions do? They prevail," Buatsi said in the ringside as he was greeted with negative reactions from the crowd.
The Londoner got back to winning after his initial pro loss - an epic battle with his previous opponent in last winter - to secure a 20th career victory.
Some ringside observers believed Parker, thirty-one, merited the win but the British boxer experienced the second setback of his 28-fight career.
The Champion Claims Triumph in Slow Encounter
The fighter's advancement has slowed in the past few years through promotional disputes and extended periods of inactivity.
Once tipped as the rising talent of British boxing, he now stands trying to realize his potential - maybe in what feels like a final roll of the dice - under recent support.
He began cautiously, with the two boxers prepared to be aggressive in a cagey early stages.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at light heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who operated with a tight guard to edge the cleaner rounds.
The spectators' acceptance diminished amid constant clinching, with the challenger going down multiple occasions during close exchanges.
The underdog closed well, but many rounds were difficult to score. Although, previous titleholder the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
The victor advances, but with the caliber of power puncher Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Ricky Hatton Memorial Fuels Local Rivalry Fight
In the co-main event, Arthur overcame Bradley Rea by divided decision in a outstanding Manchester vs Manchester contest to win the European light heavyweight title.
The stadium became quiet for a deeply poignant homage before the fight as ten bells tolled in remembrance of local hero Hatton, who succumbed 46 years old in recently.
It was the initial significant broadcast match card in the city since the passing of Hatton. As the final chime faded, the quiet gave way to a shout of "there's just one Ricky Hatton".
The fighting inside the ropes equaled the feeling. The eventual winner was knocked down by a left hook directly to the chin in the second round, rising shakily to his footing on the referee's count.
But the traditional red equipment of Arthur soon came forward again. From the other corner, Rea - in rival City blue - was injured early, noticeable damage forming under his eye as the pair landed powerful shots.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, responded in kind with stinging uppercuts as the intensity hardly diminished over 12 rounds.
The victor edged the verdict with official scores of draw, narrow lead and 115-112, but the two athletes were persistent and full of heart, everything their idol the legend embodied.
