UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a close 10-round fight at the Manchester venue.
But Parker had his moments, delivering effective clean blows in a contest where the approaches never quite clicked, with constant grabbing marring the action.
The scoring judges scored it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my best showing but what do champions do? They prevail," the victor said in the ringside as he was greeted with disapproval from the crowd.
The British fighter got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a 20th career victory.
Various analysts thought Parker, 31, merited the victory but the contender suffered the second loss of his 28-fight career.
Buatsi Earns Triumph in Uneventful Match
His career development has stalled in the past few years through promotional disputes and long spells of inactivity.
Earlier forecast as the future of the British fight scene, he now finds himself trying to fulfil that early promise - perhaps in what seems like a final roll of the dice - under fresh management.
He began cautiously, with the two boxers ready to take risks in a cagey initial rounds.
Parker, whose single earlier setback came at super middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was participating in his second fight at light-heavyweight.
By the middle rounds, the underdog had kept it close, making life awkward for Buatsi, who worked behind a solid defense to edge the more effective periods.
The audience's tolerance wore thin during regular grabbing, with Parker going down multiple occasions during grappling.
Parker ended stronger, but several stanzas were challenging to assess. Nevertheless, ex-champion Carl Frampton - providing analysis for Dazn - had it particularly wide for Parker, scoring for Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Hatton Memorial Motivates Local Rivalry Contest
In the co-main event, Arthur overcame Rea by close verdict in a excellent local rivalry battle to capture the continental belt.
The venue fell silent for a profoundly moving homage ahead of the contest as 10 bells tolled in remembrance of Manchester's own Hatton, who passed away 46 years old in recently.
It was the first major televised fight night in the urban center since the passing of Hatton. As the last bell disappeared, the quiet transitioned to a roar of "only one Ricky Hatton".
The action within the ring reflected the sentiment. The eventual winner was floored by a left hook directly to the face in the initial stage, rising shakily to his footing on the referee's count.
But the Manchester United-red shorts of Arthur soon came forward again. On the opposite side, Rea - in opposing blue - was injured soon, significant bruising appearing under his eye as the fighters traded powerful shots.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with stinging uppercuts as the action hardly diminished over twelve rounds.
The victor barely secured the decision with scoring tallies of even score, 115-113 and clearer margin, but each competitor were persistent and brave, exactly what their inspiration the legend stood for.
