UK light heavyweight Buatsi earned a win yet disappointing start to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a close ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective clean blows in a contest where the styles didn't complement each other, with frequent clinching marring the action.
The officials judged it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest performance but how do champions respond? They win," Buatsi stated in the ringside as he was met by negative reactions from the crowd.
The Londoner got back to winning after his maiden career setback - an epic battle with his previous opponent in February - to earn a 20th pro success.
Various analysts felt Parker, thirty-one, deserved the decision but the Derbyshire fighter suffered the second loss of his 28-match career.
The Champion Claims Victory in Slow Affair
Buatsi's progress has plateaued in the past few years through management issues and extended periods of lack of fights.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to achieve expectations - possibly in what seems like a ultimate opportunity - under fresh management.
He started carefully, with both competitors ready to take risks in a tentative early stages.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second bout at the higher weight class.
By the fight's midpoint, Parker had kept it close, making life awkward for Buatsi, who worked behind a tight guard to narrowly win the cleaner stanzas.
The crowd's patience diminished during regular grabbing, with Parker going down various instances during close exchanges.
The underdog ended stronger, but multiple periods were difficult to score. Nevertheless, former world champion the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, giving Buatsi just one round.
The victor progresses, but with the likes of power puncher Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still appears challenging.
Ricky Hatton Homage Inspires Local Rivalry Battle
In the co-main event, Arthur overcame Rea by divided decision in a terrific Manchester vs Manchester fight to capture the European light heavyweight title.
The stadium fell silent for a extremely emotional memorial before the fight as ten bells rang in memory of the city's native Ricky Hatton, who succumbed 46 years old in recently.
It was the first major televised fight night in the urban center since Hatton's death. As the concluding sound ended, the silence gave way to a shout of "there's just one Hatton".
The fighting within the ring reflected the feeling. Arthur was knocked down by a powerful punch flush on the chin in the early round, standing uncertainly to his footing on the eight count.
But the Manchester United-red attire of the fighter soon advanced again. On the opposite side, the opponent - in competitive blue - was marked up quickly, heavy swelling forming under his face as the fighters exchanged powerful shots.
The challenger, 27, delivered effective strikes but Arthur, 34, matched the intensity with stinging uppercuts as the intensity rarely dropped over twelve rounds.
The victor narrowly won the decision with scoring tallies of 114-114, close margin and wider gap, but both fighters were determined and full of heart, all the qualities their idol Hatton embodied.
