British light-heavyweight Buatsi made a winning yet unimpressive start to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a majority decision in a tight ten-round bout at the Manchester venue.
But Parker found success, landing some telling clean blows in a match where the styles failed to mesh, with constant grabbing disrupting the action.
Two judges scored it 96-94 to Buatsi, with the remaining official a 95-95.
"It wasn't my greatest performance but what defines champions? They succeed," Buatsi said in the ring as he was faced disapproval from the spectators.
The British fighter bounced back after his initial pro loss - an memorable fight with his previous opponent in February - to claim a 20th pro success.
Some ringside observers thought the challenger, thirty-one, should have been awarded the victory but the British boxer experienced the second loss of his 28-match professional journey.
The Champion Claims Win in Uneventful Encounter
Buatsi's progress has plateaued in the past few years through promotional disputes and considerable time of lack of fights.
Earlier forecast as the rising talent of the British fight scene, he now is positioned trying to fulfil that early promise - possibly in what appears to be a final roll of the dice - under fresh management.
He started carefully, with neither fighter ready to be aggressive in a cagey opening few rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, creating difficulties for the favorite, who worked behind a protective stance to barely take the cleaner rounds.
The spectators' acceptance diminished amid constant clinching, with the challenger slipping to the canvas several times during grappling.
Parker ended stronger, but several stanzas were difficult to score. However, previous titleholder the boxing analyst - commentating on the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
The victor progresses, but with the caliber of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Ricky Hatton Tribute Fuels All-Manchester Battle
In the secondary fight, Arthur overcame Rea by close verdict in a outstanding local rivalry battle to win the continental title.
The arena became quiet for a profoundly moving tribute prior to the bout as ten bells tolled in honor of Manchester's own Ricky Hatton, who passed away at age 46 in last month.
It was the first major televised fight night in the location since Hatton's passing. As the final chime disappeared, the quiet gave way to a roar of "there's just one Ricky Hatton".
The fighting during the bout equaled the emotion. Arthur was sent to the canvas by a powerful punch directly to the chin in the early round, getting up unsteadily to his footing on the eight count.
But the Manchester United-red equipment of Arthur soon advanced again. On the opposite side, the opponent - in rival City blue - was marked up quickly, significant bruising appearing under his eye as the duo exchanged punishing blows.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, responded in kind with effective uppercuts as the pace seldom decreased over the full distance.
Arthur barely secured the result with judges scorecards of draw, narrow lead and wider gap, but the two athletes were determined and brave, everything their inspiration the legend represented.
