British light-heavyweight Buatsi earned a win yet unimpressive start to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a competitive ten-round contest at the boxing arena.
But Parker landed significant shots, landing some telling individual punches in a fight where the styles never quite clicked, with frequent clinching spoiling the action.
The scoring judges scored it 96-94 for to Buatsi, with the third a even score.
"It wasn't my greatest display but what defines champions? They succeed," the victor said in the ringside as he was met by disapproval from the crowd.
The British fighter returned to winning ways after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th career victory.
Some ringside observers felt Parker, 31, merited the win but the contender endured the second defeat of his 28-bout professional journey.
The Champion Earns Triumph in Uneventful Affair
Buatsi's progress has slowed in the past few years through promotional disputes and long spells of inactivity.
Earlier forecast as the rising talent of UK boxing, he now stands trying to achieve expectations - maybe in what seems like a ultimate opportunity - under new promotional backing.
He began cautiously, with both competitors ready to be aggressive in a cagey opening few rounds.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after suffering a hand injury in the contest, was participating in his second appearance at the higher weight class.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who operated with a protective stance to edge the more effective stanzas.
The spectators' acceptance diminished because of regular grabbing, with the challenger falling to the floor various instances during close exchanges.
Parker ended stronger, but many rounds were challenging to assess. However, former world champion Carl Frampton - commentating on Dazn - had it particularly wide for Parker, awarding Buatsi just only one stanza.
Buatsi moves on, but with the presence of heavy hitter David Benavidez, and Russian star Bivol dominating the weight class, the journey to titles - judging by this showing - still looks steep.
Ricky Hatton Memorial Fuels Manchester Derby Contest
In the co-main event, Arthur overcame Bradley Rea by close verdict in a terrific Manchester vs Manchester battle to secure the European light heavyweight championship.
The stadium grew hushed for a profoundly moving homage before the fight as ten bells sounded in memory of the city's native Hatton, who died 46 years old in last month.
It was the first major televised match card in the urban center since Hatton's death. As the last bell faded, the quiet transitioned to a roar of "only one Ricky Hatton".
The competition within the ring reflected the emotion. Arthur was sent to the canvas by a left hook flush on the jaw in the early round, standing uncertainly to his footing on the count of eight.
But the traditional red equipment of the fighter soon came forward again. On the opposite side, the opponent - in opposing blue - was damaged early, significant bruising forming under his face as the pair exchanged punishing blows.
Rea, twenty-seven, connected with strong blows but Arthur, thirty-four, fought fire with fire with effective uppercuts as the intensity rarely dropped over 12 rounds.
The victor edged the verdict with scoring tallies of 114-114, narrow lead and 115-112, but the two athletes were persistent and courageous, all the qualities their hero Hatton stood for.
