UK light-heavyweight Buatsi made a winning yet disappointing debut to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a competitive ten-round contest at the Co-op Live Arena.
But the challenger had his moments, delivering effective single shots in a contest where the styles didn't complement each other, with constant grabbing marring the contest.
The officials had it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my best showing but what defines champions? They win," Buatsi stated in the ring as he was faced disapproval from the audience.
The British fighter got back to winning after his first professional defeat - an epic battle with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts thought the challenger, 31, should have been awarded the win but the Derbyshire fighter endured the second loss of his 28-bout career.
The Champion Earns Victory in Uneventful Affair
His career development has plateaued in recent times through management issues and extended periods of inactivity.
Earlier forecast as the future of the British fight scene, he now is positioned trying to fulfil that early promise - possibly in what appears to be a final roll of the dice - under fresh management.
He opened tentatively, with neither fighter willing to overcommit in a tentative early stages.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after breaking his hand in the contest, was competing in only his second bout at light heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for Buatsi, who utilized a tight guard to narrowly win the cleaner stanzas.
The spectators' acceptance decreased because of regular grabbing, with Parker slipping to the canvas several times during close exchanges.
The underdog closed well, but several stanzas were challenging to assess. Nevertheless, former world champion the boxing analyst - working with Dazn - had it strongly leaning for Parker, giving Buatsi just a single round.
Buatsi advances, but with the likes of hard hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Hatton Homage Inspires Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Rea by divided decision in a outstanding all-Manchester battle to capture the European light heavyweight belt.
The venue fell silent for a extremely emotional tribute prior to the bout as 10 bells rang in memory of local hero Hatton, who died at age 46 in last month.
It was the premier televised boxing event in the city since Hatton's passing. As the last bell ended, the stillness gave way to a roar of "there's only one Ricky Hatton".
The action during the bout equaled the sentiment. Arthur was sent to the canvas by a significant blow squarely on the chin in the second round, standing uncertainly to his feet on the eight count.
But the traditional red equipment of the fighter soon advanced again. Across the ring, Rea - in rival City blue - was damaged early, heavy swelling developing under his eye as the fighters landed punishing blows.
Rea, 27, connected with strong blows but the champion, thirty-four, responded in kind with stinging uppercuts as the action hardly diminished over the full distance.
The victor narrowly won the verdict with scoring tallies of draw, 115-113 and clearer margin, but the two athletes were relentless and courageous, exactly what their hero Hatton represented.
