British light heavyweight Buatsi earned a win yet underwhelming start to his career under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a competitive 10-round bout at the boxing arena.
But Parker had his moments, connecting with powerful individual punches in a match where the techniques never quite clicked, with frequent clinching spoiling the contest.
The scoring judges had it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my best performance but what defines champions? They win," the victor stated in the ring as he was met by negative reactions from the audience.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to secure a 20th career victory.
Some ringside observers believed Parker, 31, should have been awarded the victory but the contender endured the second setback of his 28-fight career.
Buatsi Secures Triumph in Slow Encounter
Buatsi's progress has plateaued in recent years through promotional disputes and extended periods of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to fulfil that early promise - maybe in what feels like a ultimate opportunity - under new promotional backing.
He opened tentatively, with both competitors ready to take risks in a cagey initial rounds.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand mid-fight, was making just his second appearance at the higher weight class.
By the halfway stage, Parker had made it competitive, making life awkward for the favorite, who utilized a protective stance to edge the more effective periods.
The audience's tolerance diminished amid frequent holding, with Parker going down various instances during grappling.
The underdog finished the stronger, but several stanzas were hard to judge. Nevertheless, former world champion Carl Frampton - commentating on Dazn - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor advances, but with the likes of power puncher Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - on this evidence - still seems difficult.
Hatton Memorial Motivates Local Rivalry Fight
In the co-main event, Arthur beat Rea by close verdict in a terrific local rivalry fight to secure the continental championship.
The stadium fell silent for a extremely emotional tribute before the fight as a bell ceremony sounded in remembrance of Manchester's own Ricky Hatton, who passed away aged 46 in last month.
It was the initial significant broadcast boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the stillness gave way to a roar of "only one Ricky Hatton".
The action during the bout equaled the sentiment. The eventual winner was knocked down by a left hook flush on the face in the initial stage, standing uncertainly to his position on the count of eight.
But the red-colored attire of the fighter soon came forward again. Across the ring, Rea - in rival City blue - was damaged early, significant bruising forming under his eye as the duo traded hard punches.
Rea, 27, delivered effective strikes but the champion, thirty-four, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
Arthur barely secured the result with judges scorecards of even score, close margin and wider gap, but both fighters were persistent and full of heart, exactly what their hero the legend stood for.
