British light-heavyweight Buatsi made a winning yet unimpressive debut to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a tight ten-round contest at the Manchester venue.
But the challenger landed significant shots, delivering effective individual punches in a contest where the styles failed to mesh, with excessive holding disrupting the contest.
The officials judged it 96-94 to Buatsi, with the third a even score.
"It wasn't my finest performance but what defines champions? They succeed," Buatsi stated in the ring as he was met by boos from the spectators.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a 20th career victory.
Some ringside observers thought the challenger, thirty-one, merited the decision but the Derbyshire fighter suffered the second defeat of his 28-fight career.
The Champion Secures Win in Dull Match
The fighter's advancement has stalled in the past few years through promotional disputes and long spells of inactivity.
Once tipped as the next star of the British fight scene, he now finds himself trying to fulfil that early promise - possibly in what feels like a last chance - under fresh management.
He opened tentatively, with both competitors ready to overcommit in a cagey opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after damaging his hand in the contest, was competing in only his second fight at the higher weight class.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who worked behind a tight guard to narrowly win the better stanzas.
The crowd's patience decreased during constant clinching, with Parker falling to the floor several times during clinches.
The underdog ended stronger, but multiple periods were difficult to score. However, former world champion Carl Frampton - working with Dazn - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
Buatsi advances, but with the likes of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Hatton Tribute Motivates Local Rivalry Fight
In the supporting bout, Lyndon Arthur defeated Bradley Rea by close verdict in a excellent Manchester vs Manchester contest to win the European light-heavyweight title.
The arena fell silent for a profoundly moving memorial prior to the bout as 10 bells rang in honor of the city's native Ricky Hatton, who passed away at age 46 in recently.
It was the premier televised boxing event in the location since Hatton's passing. As the concluding sound ended, the silence gave way to a chant of "only one Ricky Hatton".
The fighting within the ring equaled the feeling. Arthur was sent to the canvas by a left hook flush on the chin in the early round, rising shakily to his feet on the referee's count.
But the red-colored attire of Arthur soon pressed ahead again. Across the ring, the opponent - in opposing blue - was marked up soon, heavy swelling developing under his eye as the pair exchanged hard punches.
Rea, 27, landed power punches but the champion, 34, responded in kind with powerful upward punches as the intensity rarely dropped over twelve rounds.
The victor narrowly won the result with official scores of 114-114, 115-113 and 115-112, but both fighters were persistent and full of heart, exactly what their hero Hatton stood for.
