UK light heavyweight Buatsi secured a victory yet disappointing start to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a split decision in a close 10-round contest at the Manchester venue.
But the challenger found success, delivering effective single shots in a fight where the styles didn't complement each other, with excessive holding marring the action.
Two judges had it 96-94 for to the winner, with the final judge a even score.
"It wasn't my best showing but what do champions do? They prevail," Buatsi commented in the ringside as he was greeted with boos from the spectators.
The British fighter returned to winning ways after his initial pro loss - an epic battle with his previous opponent in February - to secure a 20th career victory.
Several boxing experts felt the challenger, 31, merited the victory but the Derbyshire fighter endured the second loss of his 28-bout career.
The Champion Earns Victory in Slow Match
Buatsi's progress has slowed in recent years through management issues and considerable time of lack of fights.
Earlier forecast as the rising talent of UK boxing, he now finds himself trying to realize his potential - possibly in what appears to be a last chance - under recent support.
He started carefully, with both competitors willing to take risks in a calculated early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after breaking his hand during the bout, was participating in his second appearance at the higher weight class.
By the fight's midpoint, the underdog had stayed in contention, causing problems for Buatsi, who worked behind a protective stance to narrowly win the more effective periods.
The crowd's patience decreased amid frequent holding, with Parker falling to the floor multiple occasions during clinches.
Parker closed well, but multiple periods were hard to judge. Although, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, giving Buatsi just a single round.
The victor advances, but with the caliber of hard hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the journey to titles - judging by this showing - still looks steep.
Hatton Memorial Motivates Local Rivalry Battle
In the supporting bout, Lyndon Arthur defeated Rea by divided decision in a outstanding local rivalry battle to win the European light-heavyweight championship.
The venue fell silent for a extremely emotional homage prior to the bout as ten bells rang in remembrance of local hero Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the stillness transitioned to a roar of "there's just one Ricky Hatton".
The action during the bout equaled the feeling. Arthur was floored by a powerful punch directly to the jaw in the initial stage, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red shorts of the fighter soon came forward again. On the opposite side, the opponent - in competitive blue - was injured quickly, significant bruising developing under his face as the fighters landed hard punches.
The challenger, 27, landed power punches but Arthur, thirty-four, fought fire with fire with powerful upward punches as the action rarely dropped over the full distance.
Arthur edged the result with judges scorecards of even score, 115-113 and clearer margin, but both fighters were relentless and full of heart, all the qualities their idol Hatton represented.
