British light heavyweight Buatsi made a winning yet disappointing debut to life under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a judges' verdict in a competitive ten-round bout at the Manchester venue.
But the challenger found success, connecting with powerful clean blows in a contest where the techniques didn't complement each other, with constant grabbing spoiling the contest.
The officials judged it 96-94 to the winner, with the final judge a 95-95.
"It wasn't my greatest display but what defines champions? They prevail," Buatsi stated in the ringside as he was greeted with negative reactions from the crowd.
The British fighter got back to winning after his first professional defeat - an epic battle with Callum Smith in last winter - to earn a 20th career victory.
Various analysts felt Parker, thirty-one, merited the decision but the contender suffered the second setback of his 28-bout professional journey.
The Champion Earns Victory in Uneventful Affair
The fighter's advancement has plateaued in recent years through contract problems and long spells of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to realize his potential - maybe in what feels like a ultimate opportunity - under new promotional backing.
He started carefully, with both competitors willing to take risks in a calculated opening few rounds.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after breaking his hand mid-fight, was making just his second bout at light-heavyweight.
By the halfway stage, Parker had kept it close, causing problems for the favorite, who utilized a protective stance to narrowly win the cleaner rounds.
The spectators' acceptance diminished amid regular grabbing, with the challenger going down multiple occasions during clinches.
The underdog finished the stronger, but several stanzas were hard to judge. However, ex-champion the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, giving Buatsi just only one stanza.
The victor progresses, but with the presence of power puncher David Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Hatton Memorial Fuels Manchester Derby Battle
In the supporting bout, Arthur overcame Rea by divided decision in a terrific local rivalry fight to secure the European light heavyweight championship.
The stadium fell silent for a extremely emotional homage prior to the bout as a bell ceremony sounded in memory of local hero Ricky Hatton, who died aged 46 in recently.
It was the initial significant broadcast fight night in the city since Hatton's passing. As the final chime disappeared, the silence gave way to a shout of "only one Ricky Hatton".
The action inside the ropes reflected the sentiment. Arthur was knocked down by a significant blow squarely on the chin in the early round, getting up unsteadily to his position on the eight count.
But the Manchester United-red attire of the fighter soon pressed ahead again. From the other corner, the opponent - in rival City blue - was damaged quickly, noticeable damage developing under his orbital area as the pair traded powerful shots.
Rea, 27, delivered effective strikes but the champion, 34, matched the intensity with effective uppercuts as the intensity seldom decreased over the full distance.
The victor edged the verdict with scoring tallies of draw, narrow lead and wider gap, but both fighters were persistent and courageous, everything their idol Hatton represented.
