UK light heavyweight Buatsi secured a victory yet disappointing beginning to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a competitive ten-round fight at the Manchester venue.
But the challenger found success, landing some telling individual punches in a fight where the styles didn't complement each other, with excessive holding marring the fight.
The officials judged it 96-94 to the winner, with the remaining official a even score.
"It wasn't my greatest display but what do champions do? They succeed," the victor said in the arena as he was met by negative reactions from the crowd.
The British fighter got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to earn a 20th career victory.
Several boxing experts felt Parker, thirty-one, merited the victory but the contender experienced the second loss of his 28-fight professional journey.
Buatsi Earns Triumph in Slow Affair
His career development has stalled in recent times through management issues and extended periods of inactivity.
Previously predicted as the future of UK boxing, he now is positioned trying to realize his potential - maybe in what seems like a last chance - under new promotional backing.
He opened tentatively, with the two boxers prepared to overcommit in a cagey early stages.
The challenger, whose single earlier setback came at super middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was participating in his second bout at light-heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for the favorite, who worked behind a tight guard to narrowly win the cleaner stanzas.
The crowd's patience diminished during frequent holding, with the challenger slipping to the canvas various instances during clinches.
The underdog closed well, but several stanzas were hard to judge. However, ex-champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, awarding Buatsi just only one stanza.
The victor progresses, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - based on this performance - still looks steep.
Ricky Hatton Tribute Fuels Manchester Derby Contest
In the co-main event, Lyndon Arthur beat Rea by divided decision in a outstanding Manchester vs Manchester battle to win the European light heavyweight championship.
The arena became quiet for a deeply poignant tribute ahead of the contest as a bell ceremony rang in memory of Manchester's own Hatton, who succumbed aged 46 in last month.
It was the premier televised fight night in the urban center since Hatton's passing. As the last bell disappeared, the silence transitioned to a shout of "only one Hatton".
The competition during the bout equaled the emotion. The eventual winner was floored by a left hook flush on the chin in the second round, standing uncertainly to his feet on the eight count.
But the traditional red equipment of the fighter soon advanced again. From the other corner, the opponent - in rival City blue - was damaged early, noticeable damage appearing under his face as the fighters landed punishing blows.
The challenger, 27, landed power punches but Arthur, thirty-four, responded in kind with stinging uppercuts as the action hardly diminished over the full distance.
Arthur edged the result with judges scorecards of draw, 115-113 and 115-112, but both fighters were relentless and brave, exactly what their hero Hatton represented.
