UK light-heavyweight Buatsi earned a win yet disappointing debut to his career under recent management with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a majority decision in a competitive 10-round fight at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective single shots in a fight where the approaches failed to mesh, with constant grabbing disrupting the contest.
Two judges scored it 96-94 in favor to the winner, with the third a even score.
"It wasn't my finest showing but what defines champions? They prevail," the victor stated in the ringside as he was faced disapproval from the spectators.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in February - to earn a 20th pro success.
Some ringside observers believed Parker, 31, merited the decision but the Derbyshire fighter experienced the second loss of his 28-bout career.
Buatsi Secures Triumph in Slow Affair
Buatsi's progress has plateaued in recent years through contract problems and long spells of inactivity.
Earlier forecast as the rising talent of British boxing, he now stands trying to realize his potential - possibly in what seems like a final roll of the dice - under new promotional backing.
He began cautiously, with the two boxers prepared to be aggressive in a tentative initial rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second appearance at the higher weight class.
By the fight's midpoint, Parker had made it competitive, causing problems for Buatsi, who operated with a tight guard to barely take the cleaner rounds.
The audience's tolerance decreased amid constant clinching, with Parker going down several times during close exchanges.
The underdog ended stronger, but several stanzas were challenging to assess. However, ex-champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for the challenger, scoring for Buatsi just one round.
The victor advances, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Hatton Homage Inspires Local Rivalry Fight
In the co-main event, Arthur overcame Bradley Rea by close verdict in a excellent all-Manchester contest to win the European light-heavyweight title.
The stadium became quiet for a extremely emotional homage before the fight as 10 bells rang in honor of Manchester's own Ricky Hatton, who succumbed aged 46 in September.
It was the initial significant broadcast boxing event in the city since the passing of Hatton. As the final chime faded, the silence transitioned to a roar of "there's only one Hatton".
The action within the ring reflected the emotion. Arthur was knocked down by a powerful punch flush on the chin in the second round, rising shakily to his footing on the count of eight.
But the red-colored shorts of Arthur soon pressed ahead again. Across the ring, Rea - in competitive blue - was damaged soon, significant bruising appearing under his orbital area as the pair exchanged powerful shots.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the pace hardly diminished over twelve rounds.
The victor narrowly won the result with official scores of even score, narrow lead and wider gap, but the two athletes were relentless and courageous, all the qualities their inspiration the legend represented.
