UK light heavyweight Buatsi made a winning yet unimpressive start to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a competitive ten-round fight at the boxing arena.
But the challenger had his moments, landing some telling clean blows in a match where the styles failed to mesh, with constant grabbing marring the contest.
Two judges scored it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my greatest performance but what do champions do? They succeed," Buatsi commented in the ring as he was greeted with negative reactions from the crowd.
The Londoner returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in February - to earn a 20th pro success.
Some ringside observers thought Parker, 31, deserved the win but the contender experienced the second loss of his 28-fight professional journey.
Buatsi Claims Triumph in Uneventful Match
His career development has stalled in the past few years through contract problems and long spells of inactivity.
Earlier forecast as the next star of the British fight scene, he now is positioned trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with both competitors prepared to be aggressive in a tentative initial rounds.
The challenger, whose single earlier setback came at super middleweight against John Ryder in two years ago after damaging his hand during the bout, was making just his second bout at light-heavyweight.
By the halfway stage, Parker had kept it close, making life awkward for Buatsi, who utilized a protective stance to edge the better periods.
The audience's tolerance diminished because of regular grabbing, with Parker going down various instances during close exchanges.
The underdog closed well, but multiple periods were challenging to assess. Nevertheless, former world champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi advances, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the journey to titles - based on this performance - still appears challenging.
Ricky Hatton Homage Motivates All-Manchester Battle
In the supporting bout, Lyndon Arthur defeated Rea by split-decision in a terrific all-Manchester battle to capture the European light heavyweight championship.
The venue became quiet for a deeply poignant memorial prior to the bout as a bell ceremony sounded in memory of local hero Ricky Hatton, who died at age 46 in recently.
It was the first major televised boxing event in the location since Hatton's passing. As the final chime faded, the silence gave way to a roar of "only one Hatton".
The action inside the ropes equaled the feeling. The eventual winner was sent to the canvas by a left hook flush on the jaw in the second round, standing uncertainly to his position on the referee's count.
But the red-colored equipment of Arthur soon advanced again. Across the ring, the opponent - in rival City blue - was marked up quickly, noticeable damage forming under his eye as the fighters exchanged powerful shots.
Rea, twenty-seven, delivered effective strikes but Arthur, thirty-four, responded in kind with powerful upward punches as the pace rarely dropped over 12 rounds.
Arthur narrowly won the decision with judges scorecards of even score, close margin and 115-112, but the two athletes were determined and brave, everything their inspiration Hatton embodied.
