British light-heavyweight Buatsi earned a win yet underwhelming beginning to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a tight ten-round fight at the Manchester venue.
But the challenger had his moments, connecting with powerful individual punches in a fight where the styles never quite clicked, with frequent clinching marring the action.
The scoring judges scored it 96-94 to the winner, with the final judge a even score.
"It wasn't my greatest showing but what defines champions? They succeed," Buatsi stated in the ringside as he was met by boos from the audience.
The British fighter returned to winning ways after his initial pro loss - an thrilling contest with Callum Smith in February - to earn a 20th pro success.
Various analysts thought Parker, 31, merited the win but the Derbyshire fighter suffered the second defeat of his 28-match professional journey.
The Champion Claims Victory in Dull Affair
Buatsi's progress has plateaued in the past few years through management issues and long spells of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to fulfil that early promise - perhaps in what feels like a last chance - under new promotional backing.
He opened tentatively, with neither fighter ready to be aggressive in a tentative early stages.
The challenger, whose single earlier setback came at super middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was participating in his second bout at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for Buatsi, who worked behind a protective stance to barely take the cleaner periods.
The audience's tolerance decreased amid regular grabbing, with the challenger going down several times during close exchanges.
The underdog ended stronger, but multiple periods were difficult to score. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just a single round.
The victor moves on, but with the caliber of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Hatton Homage Motivates All-Manchester Contest
In the supporting bout, Arthur overcame Rea by close verdict in a outstanding local rivalry fight to secure the European light heavyweight title.
The stadium fell silent for a profoundly moving tribute before the fight as 10 bells tolled in memory of local hero Hatton, who died at age 46 in September.
It was the initial significant broadcast match card in the urban center since Hatton's death. As the final chime faded, the silence became a chant of "only one Ricky Hatton".
The fighting within the ring equaled the feeling. The eventual winner was sent to the canvas by a left hook directly to the chin in the initial stage, getting up unsteadily to his footing on the eight count.
But the red-colored equipment of Arthur soon advanced again. Across the ring, Rea - in rival City blue - was damaged quickly, significant bruising appearing under his eye as the duo traded punishing blows.
The challenger, twenty-seven, landed power punches but the champion, thirty-four, responded in kind with stinging uppercuts as the action seldom decreased over the full distance.
The victor edged the result with judges scorecards of 114-114, close margin and clearer margin, but the two athletes were persistent and brave, everything their inspiration Hatton represented.
