UK light-heavyweight Buatsi earned a win yet unimpressive start to his career under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic bronze medallist's work rate appeared to earn him a judges' verdict in a tight ten-round contest at the Co-op Live Arena.
But the challenger found success, delivering effective individual punches in a fight where the approaches didn't complement each other, with frequent clinching disrupting the action.
Two 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 arena as he was greeted with negative reactions from the spectators.
The British fighter returned to winning ways after his maiden career setback - an epic battle with his previous opponent in last winter - to claim a 20th pro success.
Various analysts believed the challenger, thirty-one, deserved the win but the contender endured the second defeat of his 28-fight professional journey.
The Champion Secures Victory in Slow Affair
Buatsi's progress has slowed in the past few years through contract problems and considerable time of inactivity.
Earlier forecast as the rising talent of the British fight scene, he now is positioned trying to realize his potential - possibly in what appears to be a last chance - under fresh management.
He started carefully, with both competitors willing to take risks in a tentative early stages.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after breaking his hand during the bout, was making just his second appearance at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for Buatsi, who worked behind a tight guard to narrowly win the better stanzas.
The audience's tolerance decreased because of frequent holding, with Parker falling to the floor multiple occasions during close exchanges.
The underdog closed well, but many rounds were challenging to assess. Nevertheless, ex-champion Carl Frampton - commentating on Dazn - had it particularly wide for the challenger, awarding Buatsi just only one stanza.
The victor advances, but with the caliber of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Hatton Tribute Motivates Local Rivalry Contest
In the co-main event, Arthur overcame Bradley Rea by split-decision in a terrific all-Manchester fight to win the European light-heavyweight belt.
The venue became quiet for a extremely emotional tribute prior to the bout as a bell ceremony tolled in honor of the city's native Hatton, who succumbed at age 46 in last month.
It was the initial significant broadcast match card in the urban center since Hatton's passing. As the final chime faded, the quiet became a chant of "only one Ricky Hatton".
The fighting within the ring reflected the feeling. The eventual winner was knocked down by a left hook squarely on the face in the early round, getting up unsteadily to his feet on the referee's count.
But the red-colored shorts of Arthur soon came forward again. Across the ring, the opponent - in opposing blue - was damaged early, significant bruising appearing under his orbital area as the duo traded powerful shots.
The challenger, 27, landed power punches but Arthur, thirty-four, responded in kind with stinging uppercuts as the intensity rarely dropped over twelve rounds.
Arthur edged the decision with official scores of 114-114, close margin and clearer margin, but the two athletes were determined and courageous, everything their hero the legend represented.
