UK light heavyweight Buatsi earned a win yet unimpressive start to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a split decision in a competitive ten-round contest at the boxing arena.
But Parker landed significant shots, connecting with powerful clean blows in a match where the approaches never quite clicked, with constant grabbing disrupting the fight.
The scoring judges judged it 96-94 for to the winner, with the remaining official a 95-95 draw.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi stated in the ringside as he was met by negative reactions from the crowd.
The Londoner bounced back after his maiden career setback - an thrilling contest with his previous opponent in last winter - to secure a 20th pro success.
Some ringside observers thought the challenger, thirty-one, should have been awarded the win but the contender endured the second defeat of his 28-match professional journey.
Buatsi Secures Triumph in Dull Encounter
The fighter's advancement has plateaued in the past few years through promotional disputes and considerable time of inactivity.
Earlier forecast as the next star of the British fight scene, he now stands trying to realize his potential - maybe in what feels like a final roll of the dice - under recent support.
He opened tentatively, with the two boxers prepared to take risks in a tentative initial rounds.
The challenger, whose single earlier setback came at super-middleweight against his former opponent in 2022 after suffering a hand injury in the contest, was competing in only his second bout at light-heavyweight.
By the halfway stage, Parker had stayed in contention, making life awkward for Buatsi, who operated with a solid defense to edge the better rounds.
The crowd's patience wore thin during frequent holding, with Parker going down several times during close exchanges.
The underdog finished the stronger, but multiple periods were hard to judge. Although, former world champion Carl Frampton - working with the broadcast network - had it particularly wide for the challenger, awarding Buatsi just only one stanza.
Buatsi advances, but with the presence of hard hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Ricky Hatton Homage Inspires Manchester Derby Contest
In the supporting bout, Arthur defeated Bradley Rea by close verdict in a outstanding local rivalry fight to win the European light heavyweight belt.
The arena became quiet for a extremely emotional tribute ahead of the contest as 10 bells tolled in memory of Manchester's own Hatton, who died aged 46 in recently.
It was the initial significant broadcast fight night in the location since Hatton's passing. As the concluding sound faded, the stillness became a shout of "there's just one Ricky Hatton".
The action inside the ropes reflected the feeling. Arthur was floored by a left hook directly to the jaw in the second round, rising shakily to his position on the referee's count.
But the Manchester United-red equipment of Arthur soon advanced again. Across the ring, the opponent - in rival City blue - was injured quickly, noticeable damage developing under his orbital area as the duo exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, fought fire with fire with stinging uppercuts as the intensity hardly diminished over 12 rounds.
The victor narrowly won the result with scoring tallies of 114-114, 115-113 and 115-112, but both fighters were persistent and courageous, exactly what their inspiration the legend embodied.
