British light-heavyweight Buatsi secured a victory yet underwhelming start to life under recent management 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 tight 10-round contest at the Manchester venue.
But the challenger found success, landing some telling single shots in a match where the approaches never quite clicked, with excessive holding marring the action.
Two judges scored it 96-94 in favor to the winner, with the third a even score.
"It wasn't my best display but what defines champions? They prevail," the victor stated in the ringside as he was faced boos from the crowd.
The British fighter bounced back after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a 20th pro success.
Various analysts believed Parker, 31, merited the decision but the contender experienced the second defeat of his 28-fight career.
Buatsi Claims Triumph in Slow Match
His career development has plateaued in recent years through promotional disputes and considerable time of inactivity.
Previously predicted as the rising talent of the British fight scene, he now stands trying to achieve expectations - perhaps in what seems like a last chance - under new promotional backing.
He began cautiously, with both competitors willing to be aggressive in a tentative early stages.
Parker, whose single earlier setback came at super-middleweight against John Ryder in 2022 after suffering a hand injury during the bout, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, making life awkward for Buatsi, who worked behind a protective stance to barely take the better rounds.
The audience's tolerance wore thin because of constant clinching, with Parker falling to the floor several times during clinches.
Parker finished the stronger, but many rounds were hard to judge. Nevertheless, former world champion the boxing analyst - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just one round.
Buatsi progresses, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - based on this performance - still looks steep.
Ricky Hatton Homage Fuels Local Rivalry Fight
In the secondary fight, Lyndon Arthur beat Bradley Rea by divided decision in a terrific local rivalry contest to win the continental title.
The stadium became quiet for a extremely emotional homage ahead of the contest as a bell ceremony rang in memory of the city's native Hatton, who succumbed aged 46 in recently.
It was the premier televised boxing event in the city since Hatton's death. As the concluding sound ended, the stillness became a roar of "there's only one Hatton".
The competition inside the ropes equaled the emotion. The eventual winner was knocked down by a powerful punch directly to the face in the second round, standing uncertainly to his feet on the count of eight.
But the traditional red shorts of the fighter soon came forward again. On the opposite side, the opponent - in competitive blue - was injured soon, heavy swelling developing under his orbital area as the fighters landed hard punches.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, matched the intensity with effective uppercuts as the pace hardly diminished over 12 rounds.
The victor narrowly won the verdict with scoring tallies of 114-114, narrow lead and clearer margin, but each competitor were relentless and full of heart, all the qualities their idol the legend represented.
