UK light heavyweight Buatsi earned a win yet unimpressive start to life under new promoters 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 close ten-round fight at the Co-op Live Arena.
But Parker landed significant shots, connecting with powerful single shots in a fight where the techniques never quite clicked, with frequent clinching marring the contest.
The scoring judges had it 96-94 for to the winner, with the remaining official a even score.
"It wasn't my finest showing but what do champions do? They succeed," the victor said in the ringside as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in February - to earn a twentieth professional win.
Various analysts thought Parker, thirty-one, deserved the decision but the contender endured the second loss of his 28-match career.
Buatsi Earns Victory in Uneventful Match
The fighter's advancement has plateaued in the past few years through promotional disputes and considerable time of inactivity.
Once tipped as the future of the British fight scene, he now is positioned trying to achieve expectations - maybe in what seems like a final roll of the dice - under recent support.
He started carefully, with neither fighter ready to take risks in a calculated initial rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was participating in his second fight at light heavyweight.
By the fight's midpoint, Parker had kept it close, making life awkward for the favorite, who worked behind a solid defense to edge the more effective periods.
The audience's tolerance decreased amid constant clinching, with the challenger slipping to the canvas various instances during close exchanges.
The underdog closed well, but many rounds were hard to judge. Although, former world champion the boxing analyst - working with Dazn - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi moves on, but with the caliber of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Memorial Motivates Local Rivalry Contest
In the co-main event, Lyndon Arthur defeated Rea by split-decision in a excellent local rivalry fight to win the continental title.
The arena became quiet for a profoundly moving homage ahead of the contest as a bell ceremony tolled in honor of Manchester's own Ricky Hatton, who succumbed at age 46 in recently.
It was the initial significant broadcast boxing event in the city since Hatton's death. As the last bell faded, the silence gave way to a chant of "there's just one Ricky Hatton".
The action inside the ropes matched the sentiment. The eventual winner was floored by a powerful punch flush on the face in the initial stage, rising shakily to his footing on the eight count.
But the red-colored shorts of Arthur soon advanced again. On the opposite side, the opponent - in competitive blue - was marked up early, significant bruising appearing under his eye as the duo exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with powerful upward punches as the pace rarely dropped over the full distance.
Arthur edged the result with scoring tallies of draw, close margin and wider gap, but each competitor were determined and full of heart, everything their inspiration the legend embodied.
