UK light heavyweight Buatsi made a winning yet unimpressive beginning to his career under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level appeared to earn him a judges' verdict in a competitive ten-round fight at the Manchester venue.
But Parker had his moments, delivering effective individual punches in a match where the approaches failed to mesh, with constant grabbing disrupting the contest.
The scoring judges judged it 96-94 for to the winner, with the third a even score.
"It wasn't my finest performance but how do champions respond? They prevail," Buatsi stated in the ringside as he was met by boos from the audience.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in February - to secure a 20th pro success.
Some ringside observers thought the challenger, 31, deserved the victory but the British boxer experienced the second setback of his 28-bout professional journey.
Buatsi Secures Victory in Dull Affair
The fighter's advancement has slowed in the past few years through management issues and extended periods of inactivity.
Once tipped as the future of UK boxing, he now is positioned trying to realize his potential - maybe in what seems like a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter prepared to take risks in a cagey initial rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after damaging his hand during the bout, was competing in only his second fight at light heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who operated with a solid defense to barely take the better stanzas.
The spectators' acceptance diminished amid regular grabbing, with the challenger going down multiple occasions during clinches.
Parker ended stronger, but multiple periods were hard to judge. However, ex-champion Carl Frampton - working with the broadcast network - had it significantly in favor for the challenger, giving Buatsi just one round.
The victor progresses, but with the caliber of hard hitter David Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - based on this performance - still appears challenging.
Hatton Memorial Inspires Local Rivalry Contest
In the supporting bout, Lyndon Arthur beat Rea by close verdict in a outstanding Manchester vs Manchester fight to secure the continental championship.
The stadium grew hushed for a deeply poignant homage prior to the bout as 10 bells tolled in remembrance of Manchester's own Ricky Hatton, who died at age 46 in last month.
It was the initial significant broadcast fight night in the location since the passing of Hatton. As the final chime disappeared, the stillness gave way to a shout of "only one Ricky Hatton".
The competition during the bout equaled the feeling. The eventual winner was sent to the canvas by a powerful punch squarely on the jaw in the second round, rising shakily to his feet on the eight count.
But the Manchester United-red attire of Arthur soon advanced again. Across the ring, the opponent - in competitive blue - was damaged early, heavy swelling forming under his face as the pair traded hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, matched the intensity with effective uppercuts as the pace seldom decreased over 12 rounds.
Arthur narrowly won the decision with official scores of 114-114, close margin and wider gap, but both fighters were determined and courageous, everything their hero Hatton represented.
