British light-heavyweight Buatsi made a winning yet unimpressive beginning to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a close 10-round contest at the boxing arena.
But the challenger landed significant shots, delivering effective single shots in a match where the techniques didn't complement each other, with excessive holding disrupting the action.
Two judges scored it 96-94 to Buatsi, with the final judge a 95-95 draw.
"It wasn't my best display but what do champions do? They prevail," Buatsi said in the ringside as he was greeted with disapproval from the audience.
The British fighter returned to winning ways after his maiden career setback - an epic battle with Callum Smith in February - to secure a twentieth professional win.
Various analysts thought the challenger, 31, should have been awarded the win but the British boxer experienced the second setback of his 28-fight professional journey.
The Champion Claims Triumph in Dull Match
Buatsi's progress has plateaued in recent years through contract problems and long spells of lack of fights.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under recent support.
He began cautiously, with the two boxers prepared to take risks in a calculated opening few rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was competing in only his second bout at light-heavyweight.
By the middle rounds, Parker had made it competitive, creating difficulties for Buatsi, who utilized a solid defense to barely take the cleaner periods.
The crowd's patience decreased amid frequent holding, with Parker falling to the floor several times during clinches.
Parker closed well, but several stanzas were challenging to assess. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the caliber of heavy hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - on this evidence - still appears challenging.
Hatton Homage Inspires Manchester Derby Battle
In the secondary fight, Arthur overcame Bradley Rea by divided decision in a terrific all-Manchester contest to secure the European light heavyweight championship.
The venue fell silent for a profoundly moving memorial prior to the bout as 10 bells tolled in memory of Manchester's own Ricky Hatton, who passed away 46 years old in September.
It was the first major televised match card in the location since Hatton's passing. As the concluding sound faded, the stillness became a roar of "there's just one Ricky Hatton".
The fighting within the ring reflected the emotion. Arthur was knocked down by a significant blow directly to the face in the initial stage, getting up unsteadily to his position on the referee's count.
But the red-colored equipment of Arthur soon pressed ahead again. On the opposite side, Rea - in opposing blue - was marked up quickly, heavy swelling developing under his orbital area as the pair exchanged punishing blows.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, matched the intensity with stinging uppercuts as the intensity rarely dropped over 12 rounds.
The victor narrowly won the verdict with scoring tallies of even score, close margin and 115-112, but both fighters were determined and brave, everything their idol Hatton stood for.
