British light heavyweight Buatsi secured a victory yet unimpressive beginning to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a tight ten-round contest at the boxing arena.
But Parker found success, landing some telling individual punches in a match where the techniques never quite clicked, with constant grabbing spoiling the action.
The scoring judges scored it 96-94 to the winner, with the third a 95-95.
"It wasn't my greatest showing but what do champions do? They prevail," Buatsi commented in the ring as he was met by boos from the spectators.
The Londoner returned to winning ways after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers thought the challenger, 31, should have been awarded the decision but the Derbyshire fighter experienced the second defeat of his 28-match career.
Buatsi Earns Victory in Dull Affair
Buatsi's progress has slowed in recent times through contract problems and long spells of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He started carefully, with both competitors prepared to be aggressive in a tentative early stages.
Parker, whose only previous defeat came at the lower weight class against John Ryder in 2022 after breaking his hand in the contest, was making just his second fight at light heavyweight.
By the halfway stage, the underdog had made it competitive, causing problems for Buatsi, who utilized a solid defense to edge the cleaner periods.
The audience's tolerance diminished during regular grabbing, with the challenger going down various instances during clinches.
The underdog ended stronger, but many rounds were difficult to score. Although, previous titleholder the boxing analyst - working with Dazn - had it particularly wide for the challenger, awarding Buatsi just one round.
Buatsi moves on, but with the caliber of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Contest
In the secondary fight, Lyndon Arthur beat Rea by divided decision in a terrific Manchester vs Manchester fight to secure the continental title.
The venue grew hushed for a extremely emotional tribute before the fight as a bell ceremony tolled in honor of local hero Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the city since the passing of Hatton. As the last bell faded, the silence transitioned to a roar of "there's only one Hatton".
The action inside the ropes equaled the emotion. The eventual winner was floored by a significant blow directly to the chin in the initial stage, getting up unsteadily to his position on the referee's count.
But the traditional red shorts of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was marked up quickly, heavy swelling appearing under his face as the pair exchanged hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the action hardly diminished over the full distance.
The victor edged the result with official scores of even score, close margin and clearer margin, but each competitor were determined and courageous, all the qualities their idol Hatton represented.
