British light-heavyweight Buatsi secured a victory yet disappointing start to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a close 10-round fight at the Co-op Live Arena.
But Parker landed significant shots, delivering effective clean blows in a fight where the approaches didn't complement each other, with excessive holding marring the fight.
Two judges had it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my best performance but what do champions do? They succeed," Buatsi stated in the ring as he was met by negative reactions from the crowd.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in February - to earn a twentieth professional win.
Some ringside observers thought Parker, 31, merited the win but the British boxer endured the second loss of his 28-bout professional journey.
The Champion Earns Triumph in Dull Encounter
His career development has plateaued in recent times through contract problems and extended periods of lack of fights.
Once tipped as the next star of British boxing, he now stands trying to realize his potential - perhaps in what feels like a ultimate opportunity - under recent support.
He started carefully, with neither fighter ready to take risks in a calculated early stages.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand in the contest, was competing in only his second fight at the higher weight class.
By the middle rounds, the underdog had made it competitive, making life awkward for the favorite, who utilized a solid defense to narrowly win the cleaner rounds.
The audience's tolerance decreased because of regular grabbing, with the challenger slipping to the canvas multiple occasions during grappling.
Parker finished the stronger, but several stanzas were difficult to score. Although, previous titleholder the boxing analyst - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
Buatsi progresses, but with the presence of hard hitter Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - based on this performance - still looks steep.
Hatton Tribute Fuels Manchester Derby Contest
In the co-main event, Lyndon Arthur overcame Bradley Rea by close verdict in a terrific all-Manchester contest to capture the European light heavyweight title.
The venue fell silent for a profoundly moving homage ahead of the contest as a bell ceremony tolled in remembrance of the city's native Ricky Hatton, who succumbed aged 46 in September.
It was the first major televised match card in the urban center since Hatton's passing. As the concluding sound disappeared, the silence became a chant of "only one Ricky Hatton".
The action inside the ropes matched the feeling. The eventual winner was sent to the canvas by a significant blow flush on the face in the second round, rising shakily to his footing on the referee's count.
But the traditional red attire of Arthur soon came forward again. From the other corner, the opponent - in rival City blue - was injured quickly, heavy swelling forming under his orbital area as the pair landed hard punches.
The challenger, twenty-seven, delivered effective strikes but Arthur, thirty-four, fought fire with fire with powerful upward punches as the pace rarely dropped over 12 rounds.
The victor barely secured the decision with scoring tallies of even score, narrow lead and 115-112, but both fighters were relentless and courageous, exactly what their hero the legend embodied.
