UK light-heavyweight Buatsi made a winning yet unimpressive debut to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a judges' verdict in a tight 10-round bout at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling individual punches in a fight where the techniques didn't complement each other, with constant grabbing spoiling the fight.
The scoring judges scored it 96-94 to Buatsi, with the final judge a even score.
"It wasn't my best showing but how do champions respond? They prevail," the victor commented in the ringside as he was greeted with disapproval from the crowd.
The Londoner bounced back after his maiden career setback - an memorable fight with his previous opponent in last winter - to claim a 20th career victory.
Various analysts felt Parker, 31, merited the decision but the contender suffered the second defeat of his 28-match professional journey.
The Champion Earns Victory in Dull Match
The fighter's advancement has plateaued in recent times through promotional disputes and extended periods of inactivity.
Previously predicted as the future of British boxing, he now finds himself trying to achieve expectations - possibly in what seems like a last chance - under new promotional backing.
He began cautiously, with neither fighter ready to overcommit in a cagey initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was making just his second bout at light heavyweight.
By the middle rounds, Parker had made it competitive, causing problems for Buatsi, who utilized a solid defense to narrowly win the cleaner rounds.
The spectators' acceptance decreased amid regular grabbing, with the challenger falling to the floor various instances during clinches.
Parker finished the stronger, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just one round.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - on this evidence - still looks steep.
Hatton Tribute Motivates Local Rivalry Battle
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a excellent all-Manchester fight to secure the continental belt.
The stadium became quiet for a profoundly moving memorial ahead of the contest as ten bells sounded in honor of local hero Ricky Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast fight night in the location since Hatton's passing. As the last bell faded, the silence became a chant of "there's only one Ricky Hatton".
The action inside the ropes reflected the feeling. The eventual winner was knocked down by a significant blow directly to the face in the second round, standing uncertainly to his feet on the count of eight.
But the traditional red attire of Arthur soon pressed ahead again. Across the ring, Rea - in opposing blue - was damaged soon, noticeable damage developing under his eye as the pair landed hard punches.
The challenger, 27, delivered effective strikes but Arthur, 34, responded in kind with powerful upward punches as the pace hardly diminished over twelve rounds.
The victor barely secured the result with official scores of 114-114, close margin and wider gap, but each competitor were relentless and brave, everything their idol Hatton stood for.
