British light-heavyweight Buatsi earned a win yet unimpressive debut to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a competitive 10-round bout at the Manchester venue.
But Parker found success, landing some telling clean blows in a fight where the styles didn't complement each other, with constant grabbing marring the action.
Two judges scored it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They prevail," Buatsi stated 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 last winter - to secure a 20th pro success.
Various analysts felt the challenger, 31, merited the victory but the Derbyshire fighter suffered the second defeat of his 28-bout career.
The Champion Secures Win in Dull Encounter
The fighter's advancement has stalled in the past few years through management issues and extended periods of inactivity.
Once tipped as the future of the British fight scene, he now is positioned trying to realize his potential - perhaps in what seems like a last chance - under fresh management.
He began cautiously, with the two boxers ready to be aggressive in a calculated early stages.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second appearance at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who utilized a tight guard to narrowly win the more effective rounds.
The crowd's patience decreased because of frequent holding, with Parker falling to the floor various instances during close exchanges.
Parker ended stronger, but several stanzas were difficult to score. However, ex-champion the boxing analyst - providing analysis for Dazn - had it particularly wide for Parker, giving Buatsi just one round.
The victor moves on, but with the likes of heavy hitter Benavidez, and Russian champion Bivol leading the category, the journey to titles - judging by this showing - still seems difficult.
Hatton Tribute Motivates Local Rivalry Battle
In the secondary fight, Lyndon Arthur overcame Rea by close verdict in a terrific local rivalry contest to win the European light-heavyweight championship.
The venue grew hushed for a extremely emotional memorial ahead of the contest as ten bells tolled in memory of the city's native Ricky Hatton, who succumbed at age 46 in recently.
It was the premier televised fight night in the location since Hatton's passing. As the final chime ended, the quiet transitioned to a chant of "there's just one Hatton".
The action during the bout reflected the feeling. The eventual winner was sent to the canvas by a significant blow directly to the jaw in the initial stage, standing uncertainly to his position on the eight count.
But the traditional red equipment of the fighter soon came forward again. Across the ring, Rea - in opposing blue - was damaged early, heavy swelling developing under his orbital area as the pair exchanged punishing blows.
The challenger, 27, delivered effective strikes but the champion, thirty-four, fought fire with fire with stinging uppercuts as the action hardly diminished over 12 rounds.
The victor barely secured the verdict with judges scorecards of draw, 115-113 and 115-112, but each competitor were persistent and full of heart, all the qualities their hero Hatton represented.
