UK light-heavyweight Buatsi secured a victory yet disappointing start to life under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a majority decision in a close ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling clean blows in a match where the techniques failed to mesh, with frequent clinching disrupting the action.
The scoring judges judged it 96-94 in favor to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest display but how do champions respond? They succeed," the victor commented in the ring as he was greeted with negative reactions from the spectators.
The British fighter bounced back after his initial pro loss - an thrilling contest with Callum Smith in February - to claim a 20th pro success.
Several boxing experts felt Parker, thirty-one, merited the victory but the Derbyshire fighter experienced the second loss of his 28-bout professional journey.
The Champion Claims Triumph in Uneventful Affair
Buatsi's progress has slowed in recent years through promotional disputes and extended periods of inactivity.
Earlier forecast as the next star of British boxing, he now stands trying to realize his potential - possibly in what appears to be a final roll of the dice - under new promotional backing.
He started carefully, with both competitors ready to take risks in a tentative early stages.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after suffering a hand injury in the contest, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who operated with a solid defense to edge the cleaner periods.
The crowd's patience wore thin during frequent holding, with Parker slipping to the canvas various instances during clinches.
Parker ended stronger, but many rounds were hard to judge. Nevertheless, former world champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just a single round.
The victor progresses, but with the likes of hard hitter Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still seems difficult.
Ricky Hatton Memorial Fuels Local Rivalry Fight
In the secondary fight, Arthur defeated Bradley Rea by split-decision in a excellent local rivalry battle to win the continental championship.
The venue became quiet for a profoundly moving memorial ahead of the contest as 10 bells sounded in honor of local hero Hatton, who died at age 46 in recently.
It was the first major televised match card in the city since Hatton's death. As the concluding sound disappeared, the silence became a shout of "there's only one Hatton".
The action inside the ropes reflected the sentiment. The eventual winner was sent to the canvas by a left hook squarely on the jaw in the early round, getting up unsteadily to his footing on the eight count.
But the red-colored attire of Arthur soon came forward again. From the other corner, the opponent - in competitive blue - was marked up early, noticeable damage developing under his eye as the fighters traded powerful shots.
Rea, 27, delivered effective strikes but Arthur, thirty-four, matched the intensity with effective uppercuts as the intensity rarely dropped over twelve rounds.
Arthur barely secured the verdict with official scores of 114-114, close margin and clearer margin, but both fighters were persistent and full of heart, all the qualities their inspiration the legend embodied.
