UK light heavyweight Buatsi made a winning yet disappointing start to his career under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a split decision in a close ten-round contest at the boxing arena.
But Parker found success, landing some telling single shots in a fight where the techniques didn't complement each other, with constant grabbing marring the contest.
The officials scored it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my greatest performance but what do champions do? They win," the victor stated in the arena as he was met by negative reactions from the crowd.
The British fighter returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in February - to secure a 20th career victory.
Various analysts thought Parker, 31, merited the victory but the contender endured the second loss of his 28-bout career.
The Champion Secures Win in Dull Affair
The fighter's advancement has stalled in recent years through management issues and long spells of lack of fights.
Previously predicted as the rising talent of UK boxing, he now stands trying to realize his potential - maybe in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter willing to be aggressive in a cagey opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after damaging his hand in the contest, was participating in his second fight at light-heavyweight.
By the fight's midpoint, Parker had kept it close, causing problems for Buatsi, who worked behind a tight guard to edge the better periods.
The crowd's patience wore thin amid frequent holding, with Parker slipping to the canvas several times during close exchanges.
The underdog finished the stronger, but several stanzas were difficult to score. Nevertheless, ex-champion Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi moves on, but with the caliber of heavy hitter David Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still appears challenging.
Hatton Memorial Inspires All-Manchester Fight
In the secondary fight, Arthur beat Rea by divided decision in a terrific local rivalry battle to secure the continental championship.
The arena fell silent for a profoundly moving memorial prior to the bout as a bell ceremony sounded in remembrance of local hero Hatton, who died 46 years old in last month.
It was the initial significant broadcast boxing event in the city since the passing of Hatton. As the concluding sound disappeared, the silence became a shout of "there's only one Ricky Hatton".
The competition during the bout matched the emotion. Arthur was knocked down by a significant blow squarely on the jaw in the early round, getting up unsteadily to his feet on the referee's count.
But the red-colored attire of Arthur soon advanced again. From the other corner, the opponent - in opposing blue - was injured early, heavy swelling developing under his orbital area as the fighters traded punishing blows.
Rea, 27, landed power punches but Arthur, thirty-four, matched the intensity with stinging uppercuts as the action rarely dropped over twelve rounds.
Arthur narrowly won the result with scoring tallies of draw, 115-113 and wider gap, but both fighters were persistent and full of heart, everything their hero the legend stood for.
