British light-heavyweight Buatsi earned a win yet disappointing beginning to his career under recent management with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a competitive ten-round bout at the boxing arena.
But the challenger had his moments, landing some telling single shots in a contest where the techniques failed to mesh, with excessive holding disrupting the contest.
The scoring judges had it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my greatest display but how do champions respond? They prevail," the victor commented in the arena as he was greeted with disapproval from the spectators.
The British fighter bounced back after his initial pro loss - an epic battle with his previous opponent in February - to secure a 20th career victory.
Several boxing experts believed the challenger, 31, merited the win but the British boxer experienced the second loss of his 28-bout professional journey.
The Champion Earns Win in Dull Affair
The fighter's advancement has slowed in recent times through contract problems and long spells of lack of fights.
Once tipped as the rising talent of British boxing, he now finds himself trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He opened tentatively, with neither fighter willing to be aggressive in a tentative early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after damaging his hand during the bout, was making just his second appearance at the higher weight class.
By the fight's midpoint, Parker had kept it close, creating difficulties for the favorite, who operated with a solid defense to narrowly win the more effective stanzas.
The spectators' acceptance decreased because of constant clinching, with Parker slipping to the canvas multiple occasions during clinches.
Parker finished the stronger, but many rounds were challenging to assess. Although, ex-champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, giving Buatsi just only one stanza.
Buatsi advances, but with the caliber of hard hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Homage Fuels All-Manchester Battle
In the co-main event, Lyndon Arthur beat Bradley Rea by divided decision in a terrific all-Manchester battle to win the European light heavyweight title.
The venue fell silent for a profoundly moving tribute before the fight as 10 bells rang in remembrance of the city's native Ricky Hatton, who died at age 46 in last month.
It was the premier televised fight night in the location since the passing of Hatton. As the final chime ended, the quiet transitioned to a shout of "only one Hatton".
The action during the bout equaled the sentiment. The eventual winner was knocked down by a left hook squarely on the face in the second round, rising shakily to his position on the eight count.
But the red-colored shorts of the fighter soon came forward again. On the opposite side, Rea - in opposing blue - was injured soon, heavy swelling appearing under his face as the pair landed hard punches.
The challenger, 27, delivered effective strikes but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the action rarely dropped over 12 rounds.
Arthur narrowly won the decision with judges scorecards of even score, narrow lead and wider gap, but both fighters were relentless and full of heart, everything their idol the legend stood for.
