British light-heavyweight Buatsi secured a victory yet underwhelming debut to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a competitive 10-round contest at the Co-op Live Arena.
But Parker had his moments, connecting with powerful individual punches in a fight where the approaches didn't complement each other, with frequent clinching spoiling the fight.
The officials scored it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my greatest performance but how do champions respond? They win," the victor said in the ringside as he was greeted with boos from the audience.
The Londoner got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts thought Parker, 31, merited the victory but the contender suffered the second setback of his 28-match professional journey.
Buatsi Earns Win in Slow Affair
His career development has slowed in recent years through promotional disputes and extended periods of lack of fights.
Earlier forecast as the next star of UK boxing, he now stands trying to fulfil that early promise - maybe in what seems like a last chance - under fresh management.
He started carefully, with both competitors prepared to take risks in a cagey initial rounds.
Parker, whose single earlier setback came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was competing in only his second appearance at light heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to barely take the better rounds.
The audience's tolerance diminished during frequent holding, with Parker falling to the floor various instances during clinches.
Parker ended stronger, but multiple periods were difficult to score. Nevertheless, former world champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just only one stanza.
The victor advances, but with the likes of hard hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Tribute Fuels All-Manchester Fight
In the secondary fight, Lyndon Arthur beat Rea by split-decision in a outstanding Manchester vs Manchester battle to capture the European light-heavyweight championship.
The venue became quiet for a extremely emotional tribute before the fight as 10 bells tolled in honor of the city's native Hatton, who passed away aged 46 in last month.
It was the initial significant broadcast match card in the location since Hatton's death. As the final chime faded, the stillness became a roar of "there's only one Ricky Hatton".
The action within the ring reflected the feeling. The eventual winner was floored by a left hook flush on the face in the initial stage, getting up unsteadily to his footing on the eight count.
But the Manchester United-red equipment of the fighter soon came forward again. From the other corner, the opponent - in competitive blue - was injured early, noticeable damage developing under his face as the fighters exchanged punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with stinging uppercuts as the intensity rarely dropped over 12 rounds.
The victor edged the verdict with judges scorecards of even score, 115-113 and wider gap, but each competitor were relentless and courageous, everything their inspiration the legend embodied.
