British light heavyweight Buatsi made a winning yet unimpressive debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a judges' verdict in a tight 10-round fight at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a contest where the approaches never quite clicked, with constant grabbing marring the fight.
The officials judged it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They win," Buatsi stated in the ringside as he was greeted with boos from the audience.
The Londoner bounced back after his initial pro loss - an thrilling contest with Callum Smith in last winter - to claim a 20th career victory.
Several boxing experts thought Parker, 31, merited the decision but the contender endured the second setback of his 28-bout professional journey.
Buatsi Secures Win in Slow Encounter
The fighter's advancement has slowed in recent times through promotional disputes and considerable time of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to realize his potential - maybe in what appears to be a final roll of the dice - under recent support.
He opened tentatively, with the two boxers willing to be aggressive in a calculated early stages.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in two years ago after damaging his hand during the bout, was competing in only his second fight at the higher weight class.
By the fight's midpoint, Parker had kept it close, creating difficulties for Buatsi, who utilized a solid defense to narrowly win the better periods.
The crowd's patience wore thin because of regular grabbing, with the challenger slipping to the canvas multiple occasions during close exchanges.
The underdog ended stronger, but several stanzas were challenging to assess. Although, former world champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just one round.
Buatsi moves on, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - on this evidence - still looks steep.
Hatton Memorial Fuels Manchester Derby Contest
In the supporting bout, Lyndon Arthur defeated Bradley Rea by divided decision in a excellent all-Manchester contest to win the European light heavyweight championship.
The arena became quiet for a profoundly moving homage prior to the bout as ten bells tolled in honor of the city's native Ricky Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast match card in the location since Hatton's passing. As the final chime ended, the quiet gave way to a chant of "there's only one Ricky Hatton".
The fighting during the bout equaled the emotion. The eventual winner was knocked down by a left hook directly to the chin in the second round, standing uncertainly to his feet on the count of eight.
But the red-colored shorts of Arthur soon came forward again. From the other corner, Rea - in opposing blue - was injured quickly, significant bruising developing under his eye as the pair exchanged powerful shots.
The challenger, twenty-seven, connected with strong blows but the champion, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over twelve rounds.
The victor barely secured the verdict with official scores of even score, 115-113 and wider gap, but both fighters were relentless and full of heart, everything their idol the legend stood for.
