British light heavyweight Buatsi made a winning yet unimpressive start to his career under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a split decision in a close ten-round contest at the Co-op Live Arena.
But Parker had his moments, landing some telling single shots in a contest where the techniques didn't complement each other, with constant grabbing spoiling the contest.
The officials had it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my best showing but what defines champions? They prevail," Buatsi said in the arena as he was met by negative reactions from the spectators.
The British fighter bounced back after his initial pro loss - an epic battle with his previous opponent in last winter - to secure a 20th career victory.
Several boxing experts thought the challenger, thirty-one, deserved the win but the British boxer endured the second setback of his 28-bout professional journey.
Buatsi Claims Win in Slow Affair
His career development has stalled in recent times through promotional disputes and considerable time of lack of fights.
Earlier forecast as the future of UK boxing, he now stands trying to achieve expectations - possibly in what seems like a final roll of the dice - under recent support.
He started carefully, with both competitors willing to take risks in a calculated early stages.
The challenger, whose single earlier setback came at super middleweight against his former opponent in two years ago after breaking his hand in the contest, was participating in his second fight at light-heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for the favorite, who worked behind a tight guard to edge the more effective stanzas.
The audience's tolerance wore thin amid frequent holding, with Parker falling to the floor multiple occasions during grappling.
The underdog ended stronger, but many rounds were difficult to score. Although, former world champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Hatton Homage Inspires All-Manchester Fight
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a terrific Manchester vs Manchester battle to win the continental championship.
The venue became quiet for a deeply poignant tribute ahead of the contest as ten bells sounded in honor of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the final chime ended, the quiet became a roar of "there's only one Ricky Hatton".
The fighting inside the ropes equaled the feeling. Arthur was knocked down by a powerful punch flush on the jaw in the early round, getting up unsteadily to his position on the referee's count.
But the traditional red attire of the fighter soon came forward again. From the other corner, the opponent - in competitive blue - was injured soon, noticeable damage appearing under his face as the duo exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the pace hardly diminished over twelve rounds.
Arthur narrowly won the decision with scoring tallies of even score, close margin and 115-112, but both fighters were determined and full of heart, all the qualities their hero Hatton represented.
