UK light heavyweight Buatsi secured a victory yet underwhelming debut to life under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate seemingly secured him a majority decision in a competitive ten-round fight at the Co-op Live Arena.
But the challenger had his moments, landing some telling single shots in a match where the styles failed to mesh, with frequent clinching disrupting the fight.
The officials scored it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my best showing but how do champions respond? They prevail," Buatsi said in the ring as he was greeted with boos from the audience.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to earn a 20th career victory.
Some ringside observers believed the challenger, thirty-one, should have been awarded the victory but the contender endured the second defeat of his 28-match professional journey.
Buatsi Secures Win in Uneventful Match
Buatsi's progress has slowed in the past few years through management issues and considerable time of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to achieve expectations - perhaps in what appears to be a ultimate opportunity - under new promotional backing.
He started carefully, with the two boxers prepared to be aggressive in a cagey initial rounds.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after suffering a hand injury mid-fight, was participating in his second appearance at light heavyweight.
By the halfway stage, the underdog had stayed in contention, creating difficulties for the favorite, who utilized a solid defense to edge the more effective stanzas.
The crowd's patience diminished amid frequent holding, with Parker going down several times during close exchanges.
The underdog ended stronger, but multiple periods were hard to judge. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it significantly in favor for the challenger, giving Buatsi just one round.
The victor moves on, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Hatton Homage Fuels Manchester Derby Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by divided decision in a outstanding all-Manchester battle to secure the European light heavyweight championship.
The arena grew hushed for a extremely emotional memorial ahead of the contest as ten bells tolled in honor of Manchester's own Ricky Hatton, who died aged 46 in recently.
It was the initial significant broadcast fight night in the urban center since Hatton's passing. As the last bell disappeared, the quiet transitioned to a chant of "there's just one Ricky Hatton".
The competition within the ring matched the emotion. Arthur was sent to the canvas by a left hook squarely on the chin in the early round, standing uncertainly to his position on the eight count.
But the traditional red equipment of the fighter soon pressed ahead again. On the opposite side, Rea - in opposing blue - was injured quickly, noticeable damage appearing under his face as the pair traded hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, responded in kind with effective uppercuts as the pace seldom decreased over 12 rounds.
The victor narrowly won the verdict with judges scorecards of 114-114, close margin and wider gap, but each competitor were determined and courageous, all the qualities their hero the legend embodied.
