British light-heavyweight Buatsi secured a victory yet unimpressive debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a split decision in a close ten-round contest at the Manchester venue.
But the challenger found success, delivering effective clean blows in a fight where the approaches didn't complement each other, with frequent clinching spoiling the contest.
Two judges scored it 96-94 for to the winner, with the third a 95-95.
"It wasn't my greatest performance but how do champions respond? They win," the victor commented in the ringside as he was greeted with boos from the spectators.
The British fighter got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to secure a twentieth professional win.
Some ringside observers believed the challenger, 31, merited the decision but the contender suffered the second defeat of his 28-bout career.
Buatsi Claims Win in Dull Encounter
The fighter's advancement has stalled in the past few years through contract problems and long spells of inactivity.
Once tipped as the rising talent of British boxing, he now stands trying to achieve expectations - possibly in what feels like a final roll of the dice - under fresh management.
He began cautiously, with the two boxers prepared to overcommit in a calculated initial rounds.
The challenger, whose sole prior loss came at the lower weight class against his former opponent in two years ago after suffering a hand injury in the contest, was making just his second appearance at light-heavyweight.
By the middle rounds, the underdog had made it competitive, creating difficulties for the favorite, who operated with a solid defense to narrowly win the better stanzas.
The crowd's patience wore thin because of frequent holding, with the challenger going down several times during close exchanges.
The underdog ended stronger, but several stanzas were challenging to assess. Although, previous titleholder Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just one round.
The victor advances, but with the likes of hard hitter Benavidez, and Russian star Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Homage Inspires Manchester Derby Fight
In the supporting bout, Lyndon Arthur defeated Rea by divided decision in a excellent Manchester vs Manchester contest to secure the European light-heavyweight championship.
The stadium grew hushed for a deeply poignant tribute ahead of the contest as a bell ceremony tolled in honor of Manchester's own Ricky Hatton, who died at age 46 in September.
It was the first major televised boxing event in the location since Hatton's death. As the last bell disappeared, the quiet gave way to a shout of "there's just one Hatton".
The fighting inside the ropes equaled the feeling. Arthur was sent to the canvas by a powerful punch directly to the face in the initial stage, rising shakily to his position on the referee's count.
But the Manchester United-red attire of Arthur soon came forward again. From the other corner, the opponent - in rival City blue - was damaged early, heavy swelling appearing under his face as the pair exchanged hard punches.
Rea, 27, connected with strong blows but Arthur, thirty-four, matched the intensity with stinging uppercuts as the intensity rarely dropped over twelve rounds.
The victor edged the decision with judges scorecards of even score, 115-113 and wider gap, but each competitor were persistent and brave, exactly what their inspiration the legend stood for.
