British light-heavyweight Buatsi made a winning yet unimpressive debut to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a tight ten-round bout at the Manchester venue.
But the challenger found success, landing some telling single shots in a match where the techniques failed to mesh, with excessive holding spoiling the contest.
Two judges had it 96-94 for to Buatsi, with the final judge a even score.
"It wasn't my finest display but what do champions do? They succeed," the victor stated in the ring as he was greeted with negative reactions from the crowd.
The Londoner bounced back after his first professional defeat - an memorable fight with his previous opponent in February - to claim a 20th career victory.
Various analysts believed Parker, 31, merited the victory but the contender suffered the second setback of his 28-match professional journey.
Buatsi Claims Triumph in Slow Match
His career development has plateaued in recent times through promotional disputes and considerable time of inactivity.
Earlier forecast as the next star of British boxing, he now finds himself trying to realize his potential - maybe in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with the two boxers ready to be aggressive in a cagey opening few rounds.
Parker, whose only previous defeat came at super-middleweight against his former opponent in two years ago after breaking his hand in the contest, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who worked behind a protective stance to narrowly win the cleaner periods.
The crowd's patience diminished amid constant clinching, with the challenger slipping to the canvas various instances during grappling.
The underdog ended stronger, but multiple periods were difficult to score. Nevertheless, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, giving Buatsi just only one stanza.
The victor progresses, but with the likes of power puncher Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the road to world glory - based on this performance - still appears challenging.
Hatton Tribute Motivates All-Manchester Battle
In the supporting bout, Lyndon Arthur overcame Rea by divided decision in a outstanding all-Manchester contest to capture the European light heavyweight championship.
The stadium became quiet for a extremely emotional tribute prior to the bout as ten bells tolled in memory of local hero Ricky Hatton, who died 46 years old in September.
It was the initial significant broadcast match card in the location since Hatton's passing. As the concluding sound faded, the quiet became a roar of "there's only one Hatton".
The fighting inside the ropes equaled the sentiment. Arthur was floored by a left hook directly to the jaw in the early round, standing uncertainly to his footing on the count of eight.
But the red-colored attire of the fighter soon advanced again. Across the ring, the opponent - in competitive blue - was injured early, heavy swelling forming under his face as the duo traded hard punches.
Rea, 27, connected with strong blows but the champion, 34, fought fire with fire with stinging uppercuts as the pace seldom decreased over twelve rounds.
Arthur barely secured the decision with official scores of even score, narrow lead and wider gap, but each competitor were determined and brave, all the qualities their inspiration the legend embodied.
