UK light-heavyweight Buatsi made a winning yet unimpressive debut to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a tight 10-round fight at the boxing arena.
But Parker landed significant shots, connecting with powerful clean blows in a fight where the styles failed to mesh, with constant grabbing marring the fight.
The scoring judges scored it 96-94 to Buatsi, with the final judge a even score.
"It wasn't my greatest display but what do champions do? They prevail," the victor commented in the arena as he was met by negative reactions from the crowd.
The British fighter bounced back after his maiden career setback - an memorable fight with Callum Smith in February - to secure a 20th pro success.
Some ringside observers believed the challenger, thirty-one, merited the decision but the British boxer endured the second defeat of his 28-bout professional journey.
The Champion Claims Win in Slow Affair
His career development has plateaued in the past few years through promotional disputes and long spells of inactivity.
Earlier forecast as the future of UK boxing, he now stands trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He opened tentatively, with both competitors ready to be aggressive in a cagey opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after breaking his hand during the bout, was competing in only his second fight at light heavyweight.
By the middle rounds, Parker had stayed in contention, making life awkward for the favorite, who operated with a solid defense to barely take the more effective periods.
The audience's tolerance wore thin amid regular grabbing, with Parker falling to the floor various instances during close exchanges.
The underdog finished the stronger, but multiple periods were difficult to score. Although, previous titleholder Carl Frampton - commentating on the broadcast network - had it particularly wide for Parker, awarding Buatsi just one round.
The victor moves on, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol ruling the division, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the secondary fight, Arthur overcame Rea by close verdict in a excellent Manchester vs Manchester contest to win the European light-heavyweight belt.
The arena fell silent for a deeply poignant memorial before the fight as ten bells rang in honor of the city's native Ricky Hatton, who succumbed at age 46 in recently.
It was the first major televised boxing event in the urban center since Hatton's passing. As the last bell faded, the silence gave way to a shout of "there's just one Ricky Hatton".
The fighting inside the ropes reflected the sentiment. Arthur was floored by a powerful punch squarely on the chin in the second round, standing uncertainly to his position on the referee's count.
But the traditional red attire of Arthur soon pressed ahead again. From the other corner, the opponent - in rival City blue - was marked up quickly, significant bruising appearing under his eye as the fighters traded hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with powerful upward punches as the intensity rarely dropped over twelve rounds.
The victor barely secured the decision with scoring tallies of 114-114, narrow lead and 115-112, but the two athletes were relentless and full of heart, exactly what their inspiration Hatton represented.
