UK light-heavyweight Buatsi earned a win yet unimpressive start to his career under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a judges' verdict in a tight ten-round fight at the Manchester venue.
But the challenger landed significant shots, delivering effective single shots in a match where the approaches failed to mesh, with excessive holding marring the fight.
The officials scored it 96-94 to the winner, with the third a even score.
"It wasn't my finest showing but what do champions do? They prevail," Buatsi stated in the arena as he was greeted with disapproval from the audience.
The Londoner got back to winning after his initial pro loss - an thrilling contest with his previous opponent in February - to claim a 20th career victory.
Various analysts thought the challenger, 31, should have been awarded the win but the Derbyshire fighter endured the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Dull Encounter
Buatsi's progress has stalled in the past few years through management issues and extended periods of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to fulfil that early promise - perhaps in what feels like a final roll of the dice - under fresh management.
He opened tentatively, with both competitors willing to overcommit in a tentative early stages.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second bout at light heavyweight.
By the middle rounds, Parker had stayed in contention, creating difficulties for Buatsi, who worked behind a tight guard to barely take the better rounds.
The audience's tolerance wore thin amid frequent holding, with Parker slipping to the canvas several times during close exchanges.
Parker ended stronger, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just one round.
The victor progresses, but with the caliber of power puncher David Benavidez, and Eastern European fighter Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Ricky Hatton Memorial Motivates Manchester Derby Contest
In the co-main event, Lyndon Arthur overcame Bradley Rea by close verdict in a outstanding local rivalry contest to win the European light heavyweight title.
The stadium grew hushed for a extremely emotional tribute prior to the bout as 10 bells sounded in memory of local hero Ricky Hatton, who succumbed 46 years old in last month.
It was the first major televised match card in the location since Hatton's passing. As the final chime ended, the stillness transitioned to a roar of "there's only one Ricky Hatton".
The competition inside the ropes matched the emotion. The eventual winner was floored by a significant blow flush on the face in the early round, rising shakily to his footing on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. On the opposite side, the opponent - in competitive blue - was damaged early, noticeable damage appearing under his eye as the pair exchanged hard punches.
Rea, twenty-seven, landed power punches but the champion, 34, fought fire with fire with stinging uppercuts as the intensity hardly diminished over twelve rounds.
Arthur narrowly won the result with official scores of even score, narrow lead and 115-112, but both fighters were relentless and full of heart, all the qualities their idol Hatton embodied.
