UK light-heavyweight Buatsi made a winning yet underwhelming start to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a majority decision in a competitive ten-round contest at the Manchester venue.
But Parker found success, connecting with powerful individual punches in a contest where the styles didn't complement each other, with excessive holding spoiling the contest.
The scoring judges judged it 96-94 for to the winner, with the remaining official a 95-95.
"It wasn't my finest performance but what defines champions? They prevail," Buatsi said in the ring as he was faced negative reactions from the crowd.
The British fighter bounced back after his first professional defeat - an memorable fight with his previous opponent in last winter - to claim a twentieth professional win.
Various analysts thought the challenger, 31, merited the win but the contender suffered the second setback of his 28-match professional journey.
Buatsi Earns Triumph in Uneventful Encounter
Buatsi's progress has slowed in recent years through promotional disputes and long spells of inactivity.
Earlier forecast as the next star of UK boxing, he now stands trying to achieve expectations - possibly in what seems like a last chance - under recent support.
He opened tentatively, with both competitors willing to be aggressive in a tentative early stages.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was participating in his second appearance at the higher weight class.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who utilized a protective stance to narrowly win the cleaner stanzas.
The spectators' acceptance wore thin during regular grabbing, with Parker slipping to the canvas several times during clinches.
The underdog ended stronger, but several stanzas were hard to judge. Although, former world champion the boxing analyst - working with the broadcast network - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the presence of heavy hitter David Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Hatton Homage Inspires All-Manchester Contest
In the secondary fight, Lyndon Arthur overcame Bradley Rea by divided decision in a outstanding all-Manchester fight to capture the continental championship.
The stadium grew hushed for a extremely emotional homage prior to the bout as a bell ceremony rang in memory of the city's native Ricky Hatton, who succumbed 46 years old in September.
It was the initial significant broadcast boxing event in the city since Hatton's passing. As the final chime ended, the quiet became a roar of "there's only one Ricky Hatton".
The fighting inside the ropes matched the sentiment. The eventual winner was knocked down by a powerful punch flush on the jaw in the early round, rising shakily to his feet on the eight count.
But the red-colored attire of the fighter soon came forward again. Across the ring, Rea - in rival City blue - was injured soon, heavy swelling forming under his face as the duo landed hard punches.
The challenger, 27, connected with strong blows but the champion, 34, responded in kind with effective uppercuts as the pace rarely dropped over 12 rounds.
Arthur barely secured the verdict with judges scorecards of 114-114, close margin and clearer margin, but the two athletes were persistent and courageous, all the qualities their hero the legend represented.
