UK light-heavyweight Buatsi earned a win yet underwhelming beginning to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a competitive ten-round fight at the Manchester venue.
But the challenger had his moments, connecting with powerful clean blows in a contest where the techniques never quite clicked, with constant grabbing marring the contest.
The scoring judges scored it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest showing but what defines champions? They prevail," Buatsi said in the ring as he was met by disapproval from the audience.
The British fighter bounced back after his first professional defeat - an memorable fight with Callum Smith in last winter - to earn a twentieth professional win.
Several boxing experts felt the challenger, thirty-one, deserved the decision but the Derbyshire fighter endured the second loss of his 28-fight career.
The Champion Secures Win in Uneventful Match
His career development has plateaued in recent years through contract problems and long spells of inactivity.
Earlier forecast as the future of UK boxing, he now is positioned trying to fulfil that early promise - possibly in what seems like a final roll of the dice - under new promotional backing.
He began cautiously, with both competitors willing to take risks in a calculated early stages.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second bout at light heavyweight.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who utilized a tight guard to edge the more effective rounds.
The spectators' acceptance diminished during frequent holding, with the challenger falling to the floor various instances during clinches.
The underdog finished the stronger, but many rounds were challenging to assess. Although, previous titleholder the boxing analyst - working with Dazn - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
The victor progresses, but with the presence of power puncher David Benavidez, and Russian champion Bivol ruling the division, the journey to titles - judging by this showing - still looks steep.
Ricky Hatton Tribute Fuels All-Manchester Contest
In the secondary fight, Arthur beat Rea by split-decision in a excellent local rivalry battle to secure the continental belt.
The stadium fell silent for a profoundly moving tribute prior to the bout as 10 bells sounded in remembrance of Manchester's own Ricky Hatton, who passed away at age 46 in last month.
It was the initial significant broadcast fight night in the city since Hatton's death. As the last bell faded, the quiet transitioned to a shout of "only one Ricky Hatton".
The competition inside the ropes equaled the sentiment. The eventual winner was knocked down by a powerful punch flush on the jaw in the second round, rising shakily to his footing on the count of eight.
But the traditional red shorts of Arthur soon advanced again. Across the ring, Rea - in opposing blue - was marked up early, heavy swelling forming under his eye as the fighters exchanged punishing blows.
The challenger, 27, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the action seldom decreased over the full distance.
Arthur edged the decision with scoring tallies of draw, 115-113 and wider gap, but each competitor were relentless and courageous, exactly what their idol the legend stood for.
