UK light-heavyweight Buatsi made a winning yet disappointing start to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a majority decision in a competitive 10-round contest at the Manchester venue.
But the challenger found success, landing some telling single shots in a contest where the techniques failed to mesh, with excessive holding disrupting the fight.
Two judges scored it 96-94 to Buatsi, with the third a 95-95.
"It wasn't my best showing but what defines champions? They prevail," the victor commented in the ringside as he was faced disapproval from the audience.
The Londoner bounced back after his maiden career setback - an memorable fight with his previous opponent in February - to claim a 20th pro success.
Various analysts felt Parker, thirty-one, should have been awarded the decision but the contender experienced the second defeat of his 28-fight professional journey.
The Champion Earns Triumph in Dull Encounter
His career development has plateaued in recent times through contract problems and considerable time of inactivity.
Earlier forecast as the future of the British fight scene, he now is positioned trying to realize his potential - maybe in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with the two boxers willing to be aggressive in a tentative initial rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after breaking his hand mid-fight, was participating in his second fight at light heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for Buatsi, who worked behind a tight guard to narrowly win the better stanzas.
The audience's tolerance diminished during frequent holding, with Parker slipping to the canvas multiple occasions during close exchanges.
The underdog finished the stronger, but several stanzas were difficult to score. Nevertheless, ex-champion Carl Frampton - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just one round.
Buatsi advances, but with the presence of power puncher Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - on this evidence - still seems difficult.
Ricky Hatton Memorial Inspires All-Manchester Battle
In the supporting bout, Arthur overcame Bradley Rea by divided decision in a excellent Manchester vs Manchester fight to secure the European light heavyweight belt.
The arena grew hushed for a deeply poignant tribute prior to the bout as ten bells rang in remembrance of Manchester's own Hatton, who died at age 46 in September.
It was the initial significant broadcast match card in the city since Hatton's death. As the concluding sound disappeared, the stillness became a chant of "there's just one Ricky Hatton".
The action during the bout matched the emotion. The eventual winner was knocked down by a powerful punch flush on the chin in the second round, standing uncertainly to his footing on the referee's count.
But the traditional red equipment of Arthur soon advanced again. From the other corner, Rea - in competitive blue - was marked up quickly, noticeable damage developing under his face as the fighters traded hard punches.
Rea, 27, connected with strong blows but the champion, thirty-four, matched the intensity with stinging uppercuts as the action seldom decreased over the full distance.
The victor narrowly won the verdict with scoring tallies of even score, 115-113 and 115-112, but each competitor were relentless and courageous, exactly what their idol Hatton represented.
