British light heavyweight Buatsi earned a win yet underwhelming beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a judges' verdict in a tight 10-round contest at the Manchester venue.
But Parker found success, connecting with powerful individual punches in a fight where the techniques failed to mesh, with excessive holding marring the fight.
Two judges scored it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my greatest performance but what do champions do? They win," the victor said in the ringside as he was met by disapproval from the spectators.
The British fighter bounced back after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a 20th career victory.
Various analysts felt the challenger, thirty-one, deserved the win but the British boxer experienced the second loss of his 28-match professional journey.
The Champion Earns Victory in Uneventful Encounter
His career development has plateaued in recent years through contract problems and considerable time of inactivity.
Earlier forecast as the next star of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what feels like a last chance - under new promotional backing.
He began cautiously, with the two boxers ready to be aggressive in a calculated early stages.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in 2022 after damaging his hand in the contest, was making just his second fight at light-heavyweight.
By the halfway stage, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a tight guard to barely take the more effective rounds.
The audience's tolerance decreased amid constant clinching, with Parker going down various instances during clinches.
Parker finished the stronger, but several stanzas were difficult to score. Nevertheless, previous titleholder the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
The victor advances, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Motivates Manchester Derby Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a outstanding Manchester vs Manchester contest to win the continental championship.
The stadium fell silent for a deeply poignant memorial before the fight as a bell ceremony tolled in memory of local hero Ricky Hatton, who succumbed 46 years old in last month.
It was the premier televised fight night in the urban center since Hatton's death. As the concluding sound disappeared, the stillness transitioned to a shout of "only one Hatton".
The action within the ring reflected the sentiment. Arthur was floored by a significant blow flush on the face in the initial stage, rising shakily to his footing on the referee's count.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, the opponent - in competitive blue - was marked up quickly, noticeable damage forming under his orbital area as the duo traded hard punches.
The challenger, 27, delivered effective strikes but the champion, 34, fought fire with fire with powerful upward punches as the intensity rarely dropped over the full distance.
The victor edged the result with scoring tallies of even score, 115-113 and clearer margin, but each competitor were determined and brave, everything their inspiration Hatton represented.
