British light heavyweight Buatsi secured a victory yet underwhelming debut to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a split decision in a close ten-round bout at the Manchester venue.
But the challenger found success, landing some telling clean blows in a fight where the approaches didn't complement each other, with frequent clinching marring the fight.
Two judges scored it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest display but what do champions do? They win," the victor stated in the ring as he was faced negative reactions from the audience.
The British fighter bounced back after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a 20th career victory.
Some ringside observers felt Parker, thirty-one, deserved the decision but the Derbyshire fighter suffered the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Slow Encounter
Buatsi's progress has slowed in recent times through management issues and long spells of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a final roll of the dice - under fresh management.
He started carefully, with both competitors ready to take risks 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 damaging his hand in the contest, was participating in his second appearance at light heavyweight.
By the fight's midpoint, Parker had kept it close, making life awkward for the favorite, who utilized a tight guard to barely take the cleaner periods.
The crowd's patience decreased during constant clinching, with the challenger going down multiple occasions during clinches.
Parker finished the stronger, but several stanzas were challenging to assess. However, previous titleholder Carl Frampton - working with the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just only one stanza.
The victor advances, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Hatton Tribute Inspires Manchester Derby Contest
In the co-main event, Arthur defeated Rea by close verdict in a excellent all-Manchester contest to capture the continental belt.
The stadium fell silent for a profoundly moving tribute before the fight as 10 bells sounded in remembrance of the city's native Ricky Hatton, who passed away 46 years old in September.
It was the initial significant broadcast match card in the city since Hatton's death. As the concluding sound ended, the quiet gave way to a chant of "there's just one Ricky Hatton".
The fighting within the ring equaled the emotion. The eventual winner was knocked down by a powerful punch flush on the face in the initial stage, rising shakily to his position on the count of eight.
But the traditional red shorts of Arthur soon advanced again. Across the ring, the opponent - in rival City blue - was marked up early, significant bruising developing under his orbital area as the duo exchanged hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with powerful upward punches as the pace hardly diminished over the full distance.
Arthur barely secured the result with judges scorecards of draw, 115-113 and 115-112, but the two athletes were relentless and courageous, exactly what their idol Hatton stood for.
