UK light heavyweight Buatsi earned a win yet unimpressive start to life under fresh promotional backing with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a majority decision in a close ten-round contest at the Co-op Live Arena.
But Parker had his moments, landing some telling single shots in a fight where the approaches didn't complement each other, with constant grabbing marring the fight.
Two judges scored it 96-94 in favor to Buatsi, with the third a even score.
"It wasn't my greatest showing but what do champions do? They win," the victor said in the ring as he was greeted with disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in February - to secure a twentieth professional win.
Various analysts believed Parker, thirty-one, deserved the victory but the contender suffered the second setback of his 28-fight professional journey.
The Champion Secures Triumph in Dull Affair
Buatsi's progress has slowed in recent times through management issues and long spells of inactivity.
Earlier forecast as the future of UK boxing, he now is positioned trying to achieve expectations - maybe in what seems like a last chance - under new promotional backing.
He began cautiously, with both competitors ready to be aggressive in a cagey opening few rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after breaking his hand mid-fight, was participating in his second fight at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who worked behind a solid defense to barely take the more effective stanzas.
The crowd's patience diminished amid regular grabbing, with Parker falling to the floor various instances during clinches.
Parker finished the stronger, but multiple periods were challenging to assess. However, ex-champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor progresses, but with the likes of heavy hitter Benavidez, and Russian champion Bivol ruling the division, the road to world glory - based on this performance - still seems difficult.
Hatton Memorial Fuels All-Manchester Battle
In the supporting bout, Arthur overcame Rea by divided decision in a outstanding local rivalry contest to secure the continental championship.
The arena fell silent for a extremely emotional memorial before the fight as 10 bells tolled in remembrance of Manchester's own Ricky Hatton, who died aged 46 in recently.
It was the first major televised fight night in the city since Hatton's death. As the concluding sound ended, the stillness transitioned to a shout of "only one Ricky Hatton".
The fighting inside the ropes reflected the feeling. The eventual winner was floored by a left hook directly to the jaw in the second 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 opposing blue - was injured early, significant bruising developing under his orbital area as the pair traded powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with stinging uppercuts as the action seldom decreased over 12 rounds.
The victor edged the decision with scoring tallies of draw, 115-113 and wider gap, but each competitor were determined and courageous, everything their hero Hatton stood for.
