UK light-heavyweight Buatsi earned a win yet unimpressive start to his career under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a judges' verdict in a competitive ten-round fight at the Co-op Live Arena.
But the challenger landed significant shots, landing some telling individual punches in a match where the styles never quite clicked, with constant grabbing marring the contest.
The scoring judges had it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest performance but what do champions do? They prevail," Buatsi said in the ringside as he was met by boos from the crowd.
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.
Several boxing experts thought the challenger, 31, should have been awarded the win but the contender endured the second loss of his 28-fight career.
Buatsi Claims Win in Dull Encounter
His career development has plateaued in recent years through management issues and considerable time of lack of fights.
Earlier forecast as the next star of British boxing, he now finds himself trying to realize his potential - maybe in what seems like a ultimate opportunity - under new promotional backing.
He began cautiously, with the two boxers willing to be aggressive in a cagey initial rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second bout at the higher weight class.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who operated with a protective stance to barely take the better periods.
The audience's tolerance wore thin during regular grabbing, with Parker slipping to the canvas multiple occasions during close exchanges.
The underdog closed well, but multiple periods were difficult to score. However, ex-champion Carl Frampton - commentating on Dazn - had it strongly leaning for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of heavy hitter Benavidez, and Russian champion Bivol ruling the division, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a terrific local rivalry battle to secure the European light heavyweight title.
The arena grew hushed for a deeply poignant tribute prior to the bout as ten bells tolled in honor of local hero Ricky Hatton, who succumbed at age 46 in recently.
It was the initial significant broadcast fight night in the urban center since the passing of Hatton. As the final chime faded, the quiet became a shout of "there's just one Ricky Hatton".
The fighting inside the ropes reflected the feeling. Arthur was floored by a powerful punch squarely on the face in the second round, standing uncertainly to his position on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. Across the ring, Rea - in competitive blue - was marked up early, heavy swelling appearing under his orbital area as the pair traded hard punches.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with effective uppercuts as the pace hardly diminished over 12 rounds.
Arthur edged the result with scoring tallies of draw, close margin and 115-112, but each competitor were determined and courageous, all the qualities their hero the legend represented.
