British light-heavyweight Buatsi secured a victory yet disappointing debut to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a judges' verdict in a close 10-round contest at the boxing arena.
But the challenger landed significant shots, connecting with powerful clean blows in a contest where the techniques never quite clicked, with excessive holding marring the action.
The officials scored it 96-94 in favor to Buatsi, with the remaining official a 95-95.
"It wasn't my finest showing but how do champions respond? They win," Buatsi said in the ringside as he was met by negative reactions from the audience.
The Londoner bounced back after his first professional defeat - an thrilling contest with his previous opponent in February - to earn a 20th pro success.
Several boxing experts thought the challenger, 31, should have been awarded the decision but the contender experienced the second defeat of his 28-fight professional journey.
Buatsi Secures Victory in Dull Match
His career development has plateaued in recent times through management issues and considerable time of lack of fights.
Once tipped as the next star of the British fight scene, he now is positioned trying to realize his potential - perhaps in what appears to be a final roll of the dice - under fresh management.
He opened tentatively, with neither fighter willing to take risks in a tentative early stages.
Parker, whose sole prior loss came at super middleweight against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second bout at light heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for the favorite, who operated with a protective stance to edge the cleaner rounds.
The crowd's patience wore thin during frequent holding, with Parker slipping to the canvas several times during close exchanges.
The underdog finished the stronger, but several stanzas were challenging to assess. Although, previous titleholder Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, scoring for Buatsi just one round.
The victor moves on, but with the likes of power puncher David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Hatton Memorial Motivates All-Manchester Fight
In the co-main event, Arthur beat Rea by close verdict in a terrific local rivalry battle to secure the European light-heavyweight title.
The arena grew hushed for a deeply poignant tribute ahead of the contest as a bell ceremony tolled in memory of the city's native Ricky Hatton, who passed away at age 46 in September.
It was the premier televised match card in the city since the passing of Hatton. As the last bell disappeared, the quiet became a chant of "there's just one Hatton".
The action within the ring equaled the emotion. The eventual winner was floored by a left hook flush on the chin in the second round, standing uncertainly to his position on the eight count.
But the traditional red equipment of Arthur soon pressed ahead again. On the opposite side, the opponent - in competitive blue - was damaged quickly, noticeable damage developing under his face as the pair traded punishing blows.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with powerful upward punches as the action seldom decreased over 12 rounds.
The victor narrowly won the verdict with scoring tallies of draw, close margin and 115-112, but both fighters were relentless and full of heart, everything their hero the legend stood for.
