British light heavyweight Buatsi made a winning yet unimpressive start to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a tight ten-round contest at the Manchester venue.
But Parker had his moments, landing some telling single shots in a match where the styles never quite clicked, with excessive holding spoiling the fight.
Two judges judged it 96-94 in favor to the winner, with the remaining official a 95-95 draw.
"It wasn't my best showing but how do champions respond? They succeed," Buatsi stated in the ring as he was faced disapproval from the crowd.
The British fighter got back to winning after his maiden career setback - an thrilling contest with Callum Smith in last winter - to claim a twentieth professional win.
Various analysts thought Parker, 31, deserved the victory but the Derbyshire fighter suffered the second loss of his 28-fight career.
The Champion Earns Victory in Slow Encounter
The fighter's advancement has stalled in recent years through contract problems and extended periods of inactivity.
Once tipped as the next star of British boxing, he now finds himself trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He began cautiously, with neither fighter ready to be aggressive in a cagey initial rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after breaking his hand mid-fight, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who worked behind a protective stance to barely take the more effective rounds.
The crowd's patience diminished amid constant clinching, with the challenger going down various instances during clinches.
The underdog ended stronger, but several stanzas were hard to judge. However, ex-champion the boxing analyst - working with Dazn - had it particularly wide for the challenger, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of power puncher David Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - based on this performance - still seems difficult.
Hatton Memorial Motivates Manchester Derby Fight
In the supporting bout, Arthur overcame Rea by divided decision in a excellent local rivalry fight to capture the continental title.
The venue fell silent for a deeply poignant homage ahead of the contest as 10 bells sounded in honor of Manchester's own Hatton, who died at age 46 in September.
It was the first major televised fight night in the city since Hatton's passing. As the concluding sound faded, the stillness became a chant of "there's just one Hatton".
The competition within the ring equaled the emotion. Arthur was floored by a powerful punch directly to the jaw in the second round, rising shakily to his feet on the count of eight.
But the traditional red shorts of the fighter soon pressed ahead again. Across the ring, the opponent - in rival City blue - was injured quickly, noticeable damage appearing under his face as the pair exchanged hard punches.
Rea, twenty-seven, connected with strong blows but Arthur, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over the full distance.
Arthur barely secured the verdict with judges scorecards of draw, 115-113 and wider gap, but the two athletes were relentless and full of heart, everything their inspiration Hatton stood for.
