UK light heavyweight Buatsi made a winning yet underwhelming debut to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a tight ten-round fight at the Co-op Live Arena.
But Parker found success, connecting with powerful clean blows in a contest where the styles didn't complement each other, with excessive holding disrupting the contest.
The officials scored it 96-94 for to Buatsi, with the third a even score.
"It wasn't my best showing but how do champions respond? They win," Buatsi said in the ringside as he was greeted with disapproval from the audience.
The British fighter returned to winning ways after his first professional defeat - an epic battle with Callum Smith in last winter - to secure a 20th pro success.
Some ringside observers believed Parker, 31, deserved the win but the Derbyshire fighter experienced the second defeat of his 28-bout career.
Buatsi Secures Triumph in Slow Match
Buatsi's progress has stalled in the past few years through management issues and long spells of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now finds himself trying to achieve expectations - possibly in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with neither fighter ready to overcommit in a cagey opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in two years ago after breaking his hand mid-fight, was competing in only his second bout at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for the favorite, who utilized a tight guard to narrowly win the more effective rounds.
The spectators' acceptance diminished amid regular grabbing, with the challenger going down various instances during close exchanges.
Parker finished the stronger, but many rounds were hard to judge. However, previous titleholder the boxing analyst - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just a single round.
Buatsi moves on, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - on this evidence - still looks steep.
Hatton Tribute Motivates Manchester Derby Contest
In the secondary fight, Arthur defeated Bradley Rea by divided decision in a outstanding all-Manchester fight to secure the European light-heavyweight belt.
The arena grew hushed for a extremely emotional homage before the fight as ten bells sounded in honor of the city's native Hatton, who passed away 46 years old in recently.
It was the premier televised match card in the location since Hatton's passing. As the final chime disappeared, the stillness transitioned to a shout of "there's only one Ricky Hatton".
The fighting inside the ropes equaled the sentiment. Arthur was sent to the canvas by a powerful punch squarely on the face in the initial stage, rising shakily to his feet on the referee's count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. Across the ring, the opponent - in opposing blue - was damaged early, significant bruising forming under his eye as the fighters traded powerful shots.
Rea, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with powerful upward punches as the intensity rarely dropped over the full distance.
Arthur barely secured the result with scoring tallies of 114-114, close margin and clearer margin, but both fighters were relentless and full of heart, all the qualities their hero Hatton stood for.
