British light heavyweight Buatsi made a winning yet disappointing start to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a split decision in a competitive ten-round bout at the Manchester venue.
But Parker landed significant shots, delivering effective single shots in a match where the styles didn't complement each other, with constant grabbing marring the fight.
The officials had it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest performance but what do champions do? They win," Buatsi commented in the ringside as he was faced boos from the crowd.
The Londoner got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Some ringside observers believed Parker, thirty-one, should have been awarded the decision but the British boxer endured the second setback of his 28-bout career.
Buatsi Claims Win in Uneventful Affair
Buatsi's progress has stalled in the past few years through management issues and considerable time of inactivity.
Previously predicted as the rising talent of UK boxing, he now is positioned trying to achieve expectations - possibly in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with both competitors willing to overcommit in a tentative opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand in the contest, was participating in his second bout at the higher weight class.
By the fight's midpoint, the underdog had stayed in contention, causing problems for the favorite, who worked behind a protective stance to narrowly win the better stanzas.
The crowd's patience wore thin because of regular grabbing, with Parker going down several times during clinches.
Parker ended stronger, but multiple periods were hard to judge. Nevertheless, previous titleholder the boxing analyst - providing analysis for Dazn - had it strongly leaning for the challenger, scoring for Buatsi just one round.
The victor advances, but with the presence of heavy hitter David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Ricky Hatton Homage Inspires All-Manchester Contest
In the co-main event, Arthur overcame Rea by split-decision in a outstanding all-Manchester battle to secure the European light-heavyweight title.
The arena fell silent for a extremely emotional memorial ahead of the contest as 10 bells rang in memory of Manchester's own Hatton, who succumbed 46 years old in last month.
It was the premier televised match card in the city since Hatton's death. As the final chime disappeared, the silence transitioned to a chant of "there's just one Hatton".
The action during the bout matched the emotion. Arthur was knocked down by a powerful punch flush on the chin in the initial stage, getting up unsteadily to his feet on the count of eight.
But the traditional red attire of Arthur soon came forward again. On the opposite side, the opponent - in opposing blue - was injured quickly, heavy swelling developing under his face as the duo exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, fought fire with fire with effective uppercuts as the action hardly diminished over twelve rounds.
The victor barely secured the decision with scoring tallies of draw, narrow lead and clearer margin, but the two athletes were determined and courageous, everything their idol Hatton represented.
