UK light-heavyweight Buatsi made a winning yet unimpressive beginning to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But Parker had his moments, connecting with powerful individual punches in a fight where the techniques never quite clicked, with constant grabbing spoiling the action.
The scoring judges scored it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but what do champions do? They win," the victor commented in the ringside as he was met by boos from the crowd.
The British fighter got back to winning after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Some ringside observers thought Parker, thirty-one, deserved the victory but the Derbyshire fighter suffered the second loss of his 28-fight career.
The Champion Earns Win in Dull Affair
His career development has stalled in the past few years through management issues and considerable time of lack of fights.
Earlier forecast as the rising talent of UK boxing, he now stands trying to realize his potential - maybe in what appears to be a last chance - under recent support.
He started carefully, with neither fighter prepared to be aggressive in a cagey early stages.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was making just his second appearance at the higher weight class.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who utilized a protective stance to narrowly win the better stanzas.
The audience's tolerance wore thin during constant clinching, with Parker slipping to the canvas several times during clinches.
Parker finished the stronger, but many rounds were difficult to score. Nevertheless, former world champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just one round.
Buatsi moves on, but with the caliber of hard hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Ricky Hatton Memorial Fuels Local Rivalry Battle
In the co-main event, Arthur beat Bradley Rea by divided decision in a outstanding all-Manchester battle to capture the European light-heavyweight championship.
The arena grew hushed for a deeply poignant memorial before the fight as 10 bells tolled in memory of local hero Ricky Hatton, who passed away aged 46 in last month.
It was the first major televised fight night in the location since the passing of Hatton. As the concluding sound ended, the silence became a chant of "there's only one Hatton".
The fighting inside the ropes matched the sentiment. Arthur was knocked down by a powerful punch flush on the chin in the early round, standing uncertainly to his position on the referee's count.
But the traditional red shorts of Arthur soon advanced again. On the opposite side, Rea - in opposing blue - was injured early, noticeable damage developing under his eye as the fighters exchanged punishing blows.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, matched the intensity with effective uppercuts as the intensity seldom decreased over the full distance.
Arthur narrowly won the decision with scoring tallies of draw, narrow lead and 115-112, but both fighters were determined and full of heart, everything their idol the legend stood for.
