UK light heavyweight Buatsi earned a win yet underwhelming start to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a tight ten-round bout at the Co-op Live Arena.
But Parker found success, landing some telling individual punches in a match where the styles failed to mesh, with constant grabbing spoiling the action.
The scoring judges scored it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi stated in the ringside as he was faced negative reactions from the audience.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in February - to claim a 20th pro success.
Various analysts felt the challenger, 31, merited the win but the contender suffered the second defeat of his 28-match career.
Buatsi Earns Victory in Slow Encounter
His career development has slowed in the past few years through contract problems and extended periods of inactivity.
Previously predicted as the rising talent of the British fight scene, he now is positioned trying to realize his potential - maybe in what feels like a last chance - under new promotional backing.
He started carefully, with the two boxers willing to be aggressive in a cagey early stages.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in two years ago after suffering a hand injury in the contest, was participating in his second bout at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for the favorite, who worked behind a tight guard to edge the cleaner rounds.
The audience's tolerance decreased during regular grabbing, with the challenger slipping to the canvas multiple occasions during grappling.
Parker ended stronger, but many rounds were hard to judge. However, ex-champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, awarding Buatsi just one round.
The victor progresses, but with the likes of hard hitter David Benavidez, and Russian star Dmitry Bivol leading the category, the path to championship success - judging by this showing - still appears challenging.
Hatton Memorial Motivates Manchester Derby Contest
In the co-main event, Arthur beat Rea by divided decision in a outstanding all-Manchester contest to secure the European light-heavyweight title.
The venue fell silent for a extremely emotional homage ahead of the contest as a bell ceremony sounded in honor of local hero Hatton, who passed away aged 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's passing. As the concluding sound ended, the silence became a chant of "there's just one Hatton".
The fighting inside the ropes equaled the feeling. Arthur was sent to the canvas by a left hook squarely on the jaw in the initial stage, standing uncertainly to his position on the referee's count.
But the traditional red attire of Arthur soon pressed ahead again. Across the ring, Rea - in competitive blue - was marked up early, significant bruising developing under his eye as the pair landed hard punches.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with effective uppercuts as the action seldom decreased over twelve rounds.
The victor edged the decision with judges scorecards of 114-114, narrow lead and 115-112, but each competitor were relentless and courageous, everything their idol the legend embodied.
