British light heavyweight Buatsi made a winning yet unimpressive debut to life under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output likely gained him a judges' verdict in a competitive ten-round bout at the Manchester venue.
But Parker landed significant shots, connecting with powerful clean blows in a match where the styles never quite clicked, with excessive holding spoiling the fight.
The officials scored it 96-94 in favor to the winner, with the remaining official a 95-95.
"It wasn't my best display but what do champions do? They win," Buatsi stated in the arena as he was faced negative reactions from the crowd.
The British fighter got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a 20th pro success.
Several boxing experts felt Parker, 31, merited the victory but the Derbyshire fighter experienced the second loss of his 28-match professional journey.
Buatsi Earns Win in Dull Affair
The fighter's advancement has stalled in recent years through management issues and considerable time of lack of fights.
Once tipped as the next star of British boxing, he now is positioned trying to realize his potential - possibly in what appears to be a final roll of the dice - under new promotional backing.
He began cautiously, with the two boxers willing to take risks in a cagey opening few rounds.
Parker, whose sole prior loss came at super-middleweight against his former opponent in two years ago after breaking his hand in the contest, was competing in only his second bout at light-heavyweight.
By the halfway stage, the underdog had kept it close, causing problems for the favorite, who operated with a solid defense to narrowly win the more effective stanzas.
The spectators' acceptance diminished amid regular grabbing, with Parker falling to the floor multiple occasions during close exchanges.
The underdog ended stronger, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, scoring for Buatsi just one round.
Buatsi moves on, but with the likes of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Memorial Fuels Local Rivalry Battle
In the supporting bout, Arthur defeated Rea by split-decision in a excellent Manchester vs Manchester fight to secure the continental title.
The stadium fell silent for a extremely emotional homage before the fight as ten bells tolled in remembrance of Manchester's own Ricky Hatton, who passed away 46 years old in last month.
It was the premier televised fight night in the city since Hatton's passing. As the concluding sound disappeared, the quiet transitioned to a shout of "only one Hatton".
The competition during the bout matched the feeling. Arthur was knocked down by a left hook squarely on the face in the second round, standing uncertainly to his feet on the eight count.
But the red-colored equipment of the fighter soon advanced again. Across the ring, the opponent - in rival City blue - was marked up quickly, significant bruising appearing under his eye as the duo exchanged punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with powerful upward punches as the intensity hardly diminished over the full distance.
The victor narrowly won the result with judges scorecards of even score, narrow lead and clearer margin, but both fighters were persistent and brave, everything their idol the legend embodied.
