British 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 appeared to earn him a split decision in a tight ten-round bout at the Co-op Live Arena.
But Parker had his moments, landing some telling individual punches in a fight where the approaches failed to mesh, with excessive holding spoiling the action.
The scoring judges judged it 96-94 to Buatsi, with the third a 95-95 draw.
"It wasn't my best showing but what defines champions? They prevail," the victor commented in the ring as he was faced disapproval from the audience.
The British fighter returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in February - to claim a twentieth professional win.
Various analysts felt Parker, 31, should have been awarded the victory but the Derbyshire fighter endured the second setback of his 28-bout professional journey.
The Champion Secures Win in Dull Affair
His career development has plateaued in recent years through promotional disputes and extended periods of lack of fights.
Previously predicted as the next star of UK boxing, he now finds himself trying to realize his potential - maybe in what appears to be a last chance - under new promotional backing.
He began cautiously, with the two boxers ready to be aggressive in a tentative initial rounds.
Parker, whose single earlier setback came at super-middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was making just his second appearance at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, causing problems for Buatsi, who worked behind a solid defense to edge the better stanzas.
The audience's tolerance diminished because of regular grabbing, with Parker going down several times during clinches.
Parker ended stronger, but several stanzas were hard to judge. Although, previous titleholder the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, scoring for Buatsi just a single round.
The victor progresses, but with the presence of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the road to world glory - based on this performance - still looks steep.
Hatton Tribute Fuels All-Manchester Contest
In the co-main event, Arthur beat Rea by close verdict in a terrific all-Manchester fight to win the European light-heavyweight title.
The venue grew hushed for a extremely emotional memorial before the fight as a bell ceremony rang in honor of Manchester's own Hatton, who died at age 46 in last month.
It was the first major televised boxing event in the location since Hatton's passing. As the last bell disappeared, the stillness transitioned to a roar of "there's just one Ricky Hatton".
The competition during the bout reflected the sentiment. The eventual winner was knocked down by a left hook squarely on the chin in the initial stage, getting up unsteadily to his feet on the eight count.
But the Manchester United-red shorts of the fighter soon advanced again. From the other corner, Rea - in competitive blue - was marked up early, noticeable damage appearing under his face as the pair landed powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, fought fire with fire with powerful upward punches as the pace seldom decreased over twelve rounds.
Arthur edged the decision with scoring tallies of 114-114, narrow lead and 115-112, but the two athletes were persistent and brave, all the qualities their inspiration Hatton represented.
