UK light heavyweight Buatsi secured a victory yet unimpressive start to life under fresh promotional backing with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a majority decision in a close ten-round fight at the Co-op Live Arena.
But Parker found success, delivering effective individual punches in a contest where the styles failed to mesh, with frequent clinching disrupting the fight.
The scoring judges scored it 96-94 to the winner, with the third a 95-95.
"It wasn't my finest showing but what defines champions? They succeed," Buatsi commented in the ringside as he was faced disapproval from the crowd.
The Londoner got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to earn a 20th pro success.
Various analysts felt the challenger, thirty-one, should have been awarded the win but the contender endured the second defeat of his 28-match career.
Buatsi Claims Triumph in Uneventful Match
The fighter's advancement has slowed in recent years through promotional disputes and long spells of inactivity.
Once tipped as the future of British boxing, he now stands trying to achieve expectations - maybe in what seems like a last chance - under fresh management.
He began cautiously, with the two boxers willing to take risks in a cagey opening few rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was participating in his second bout at the higher weight class.
By the fight's midpoint, Parker had kept it close, creating difficulties for the favorite, who worked behind a protective stance to edge the better stanzas.
The crowd's patience diminished during regular grabbing, with the challenger slipping to the canvas various instances during clinches.
Parker ended stronger, but many rounds were difficult to score. However, previous titleholder Carl Frampton - working with the broadcast network - had it strongly leaning for Parker, awarding Buatsi just one round.
The victor advances, but with the presence of heavy hitter David Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates Manchester Derby Battle
In the secondary fight, Arthur beat Rea by close verdict in a outstanding all-Manchester contest to secure the European light heavyweight championship.
The stadium became quiet for a profoundly moving homage ahead of the contest as a bell ceremony tolled in honor of local hero Hatton, who died 46 years old in recently.
It was the premier televised boxing event in the urban center since Hatton's passing. As the concluding sound disappeared, the stillness transitioned to a shout of "there's only one Ricky Hatton".
The competition during the bout reflected the sentiment. The eventual winner was knocked down by a powerful punch directly to the jaw in the second round, getting up unsteadily to his position on the referee's count.
But the red-colored attire of the fighter soon pressed ahead again. From the other corner, the opponent - in opposing blue - was marked up soon, heavy swelling forming under his face as the fighters exchanged punishing blows.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with effective uppercuts as the intensity rarely dropped over the full distance.
The victor narrowly won the verdict with judges scorecards of even score, 115-113 and 115-112, but each competitor were persistent and courageous, everything their hero Hatton stood for.
