British light heavyweight Buatsi made a winning yet unimpressive beginning to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a competitive 10-round contest at the boxing arena.
But the challenger had his moments, connecting with powerful clean blows in a match where the techniques failed to mesh, with excessive holding spoiling the fight.
The scoring judges judged it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my finest performance but what defines champions? They prevail," Buatsi commented in the arena as he was met by boos from the crowd.
The British fighter got back to winning after his first professional defeat - an epic battle with Callum Smith in last winter - to secure a 20th career victory.
Various analysts felt Parker, 31, merited the win but the Derbyshire fighter suffered the second loss of his 28-match professional journey.
Buatsi Secures Victory in Dull Affair
The fighter's advancement has slowed in recent years through promotional disputes and considerable time of lack of fights.
Once tipped as the next star of the British fight scene, he now is positioned trying to fulfil that early promise - maybe in what appears to be a final roll of the dice - under recent support.
He started carefully, with both competitors willing to overcommit in a cagey initial rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in 2022 after suffering a hand injury mid-fight, was competing in only his second fight at the higher weight class.
By the middle rounds, the underdog had made it competitive, making life awkward for the favorite, who operated with a solid defense to edge the better rounds.
The audience's tolerance decreased because of regular grabbing, with Parker slipping to the canvas various instances during grappling.
Parker ended stronger, but multiple periods were difficult to score. Although, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the caliber of heavy hitter David Benavidez, and Russian star Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Battle
In the co-main event, Lyndon Arthur beat Bradley Rea by close verdict in a excellent local rivalry fight to win the European light heavyweight belt.
The arena fell silent for a extremely emotional homage ahead of the contest as ten bells rang in remembrance of the city's native Ricky Hatton, who died at age 46 in last month.
It was the initial significant broadcast match card in the urban center since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a shout of "there's just one Ricky Hatton".
The fighting within the ring matched the feeling. The eventual winner was sent to the canvas by a powerful punch directly to the chin in the initial stage, rising shakily to his footing on the referee's count.
But the traditional red shorts of Arthur soon came forward again. Across the ring, Rea - in opposing blue - was marked up soon, heavy swelling forming under his face as the duo traded powerful shots.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, matched the intensity with stinging uppercuts as the pace hardly diminished over the full distance.
Arthur narrowly won the verdict with scoring tallies of even score, 115-113 and wider gap, but both fighters were determined and brave, everything their inspiration the legend represented.
