UK light heavyweight Buatsi secured a victory yet underwhelming debut to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a judges' verdict in a competitive ten-round contest at the Manchester venue.
But Parker had his moments, delivering effective clean blows in a match where the approaches failed to mesh, with excessive holding spoiling the contest.
The officials scored it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my finest display but what do champions do? They win," Buatsi commented in the ring as he was faced boos from the crowd.
The British fighter got back to winning after his first professional defeat - an thrilling contest with his previous opponent in February - to secure a twentieth professional win.
Several boxing experts believed the challenger, thirty-one, merited the decision but the contender experienced the second loss of his 28-fight career.
Buatsi Secures Victory in Slow Match
Buatsi's progress has plateaued in the past few years through promotional disputes and long spells of inactivity.
Once tipped as the rising talent of UK boxing, he now finds himself trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under fresh management.
He opened tentatively, with neither fighter prepared to take risks in a tentative opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after breaking his hand during the bout, was competing in only his second appearance at light heavyweight.
By the middle rounds, the underdog had stayed in contention, making life awkward for the favorite, who operated with a protective stance to narrowly win the better stanzas.
The audience's tolerance wore thin during frequent holding, with the challenger slipping to the canvas multiple occasions during grappling.
Parker finished the stronger, but many rounds were hard to judge. However, ex-champion Carl Frampton - commentating on Dazn - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the caliber of hard hitter Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Hatton Tribute Motivates Local Rivalry Contest
In the co-main event, Lyndon Arthur beat Bradley Rea by divided decision in a outstanding all-Manchester battle to win the European light-heavyweight title.
The arena fell silent for a profoundly moving tribute prior to the bout as 10 bells rang in honor of local hero Hatton, who passed away 46 years old in September.
It was the first major televised fight night in the urban center since Hatton's passing. As the last bell disappeared, the stillness gave way to a chant of "there's only one Ricky Hatton".
The competition during the bout reflected the sentiment. The eventual winner was floored by a powerful punch flush on the jaw in the early round, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon pressed ahead again. On the opposite side, the opponent - in competitive blue - was damaged soon, significant bruising forming under his face as the duo landed hard punches.
The challenger, 27, delivered effective strikes but Arthur, 34, fought fire with fire with powerful upward punches as the action rarely dropped over twelve rounds.
Arthur edged the decision with official scores of 114-114, close margin and 115-112, but each competitor were relentless and brave, everything their hero the legend represented.
