British light-heavyweight Buatsi made a winning yet unimpressive debut to life under new promoters with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level likely gained him a judges' verdict in a close 10-round fight at the boxing arena.
But Parker found success, landing some telling single shots in a match where the styles never quite clicked, with constant grabbing marring the fight.
The officials scored it 96-94 in favor to the winner, with the third a even score.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi commented in the ringside as he was faced boos from the audience.
The Londoner got back to winning after his initial pro loss - an epic battle with Callum Smith in last winter - to secure a twentieth professional win.
Several boxing experts thought Parker, thirty-one, should have been awarded the win but the contender endured the second setback of his 28-match professional journey.
Buatsi Claims Triumph in Uneventful Encounter
The fighter's advancement has stalled in recent times through promotional disputes and considerable time of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to fulfil that early promise - perhaps in what feels like a ultimate opportunity - under fresh management.
He opened tentatively, with both competitors willing to overcommit in a calculated initial rounds.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after suffering a hand injury mid-fight, was competing in only his second appearance at light heavyweight.
By the fight's midpoint, the underdog had kept it close, causing problems for the favorite, who operated with a protective stance to barely take the more effective rounds.
The audience's tolerance decreased during frequent holding, with Parker slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but several stanzas were challenging to assess. Nevertheless, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - judging by this showing - still looks steep.
Hatton Tribute Inspires Local Rivalry Contest
In the secondary fight, Lyndon Arthur defeated Rea by close verdict in a outstanding local rivalry fight to win the continental belt.
The arena grew hushed for a extremely emotional homage prior to the bout as 10 bells tolled in remembrance of local hero Hatton, who passed away aged 46 in September.
It was the first major televised fight night in the location since Hatton's death. As the last bell disappeared, the stillness became a roar of "only one Hatton".
The competition during the bout reflected the emotion. Arthur was floored by a powerful punch directly to the face in the initial stage, rising shakily to his footing on the count of eight.
But the red-colored equipment of the fighter soon pressed ahead again. On the opposite side, the opponent - in opposing blue - was injured early, noticeable damage developing under his face as the duo exchanged hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, responded in kind with stinging uppercuts as the intensity hardly diminished over twelve rounds.
The victor narrowly won the decision with official scores of draw, narrow lead and wider gap, but each competitor were determined and brave, everything their inspiration the legend stood for.
