British light-heavyweight Buatsi earned a win yet underwhelming start to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's activity level likely gained him a split decision in a tight ten-round bout at the Manchester venue.
But Parker found success, landing some telling single shots in a match where the styles failed to mesh, with frequent clinching disrupting the fight.
The scoring judges had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my finest display but what do champions do? They succeed," the victor said in the ringside as he was faced negative reactions from the spectators.
The Londoner bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a 20th career victory.
Various analysts believed the challenger, 31, should have been awarded the win but the Derbyshire fighter experienced the second defeat of his 28-fight professional journey.
The Champion Claims Win in Dull Match
His career development has stalled in recent times through contract problems and considerable time of inactivity.
Previously predicted as the rising talent of British boxing, he now finds himself trying to achieve expectations - perhaps in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with both competitors willing to be aggressive in a cagey early stages.
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 participating in his second appearance at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, causing problems for the favorite, who utilized a protective stance to edge the more effective periods.
The crowd's patience decreased during frequent holding, with Parker falling to the floor various instances during clinches.
The underdog finished the stronger, but multiple periods were hard to judge. Although, ex-champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, scoring for Buatsi just one round.
Buatsi progresses, but with the likes of power puncher David Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Homage Fuels Local Rivalry Fight
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a terrific local rivalry contest to secure the European light heavyweight belt.
The arena fell silent for a profoundly moving memorial ahead of the contest as a bell ceremony tolled in remembrance of Manchester's own Hatton, who passed away aged 46 in last month.
It was the premier televised boxing event in the location since Hatton's passing. As the final chime disappeared, the quiet gave way to a chant of "only one Hatton".
The action within the ring equaled the sentiment. Arthur was floored by a significant blow directly to the face in the second round, standing uncertainly to his position on the eight count.
But the red-colored shorts of Arthur soon advanced again. On the opposite side, the opponent - in opposing blue - was marked up quickly, significant bruising forming under his face as the fighters exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, 34, matched the intensity with effective uppercuts as the action rarely dropped over twelve rounds.
The victor edged the decision with official scores of draw, close margin and 115-112, but each competitor were persistent and courageous, everything their inspiration Hatton stood for.
