British light heavyweight Buatsi secured a victory yet disappointing start to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a split decision in a close 10-round bout at the Co-op Live Arena.
But the challenger had his moments, connecting with powerful single shots in a contest where the approaches never quite clicked, with excessive holding disrupting the contest.
The officials scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest display but what defines champions? They prevail," Buatsi said in the arena as he was faced boos from the audience.
The Londoner got back to winning after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts felt Parker, 31, should have been awarded the victory but the contender suffered the second loss of his 28-bout career.
The Champion Earns Win in Slow Match
His career development has slowed in recent times through promotional disputes and long spells of inactivity.
Once tipped as the next star of UK boxing, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under recent support.
He began cautiously, with neither fighter ready to take risks in a tentative initial rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after damaging his hand during the bout, was making just his second appearance at light-heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for Buatsi, who operated with a protective stance to edge the more effective stanzas.
The crowd's patience decreased because of regular grabbing, with Parker falling to the floor several times during clinches.
The underdog ended stronger, but multiple periods were difficult to score. Nevertheless, former world champion Carl Frampton - working with Dazn - had it strongly leaning for the challenger, awarding Buatsi just one round.
The victor moves on, but with the presence of heavy hitter Benavidez, and Eastern European fighter Bivol leading the category, the path to championship success - based on this performance - still seems difficult.
Ricky Hatton Memorial Motivates All-Manchester Contest
In the co-main event, Arthur overcame Bradley Rea by close verdict in a excellent local rivalry contest to capture the European light-heavyweight title.
The arena grew hushed for a deeply poignant homage before the fight as 10 bells tolled in honor of Manchester's own Ricky Hatton, who died aged 46 in September.
It was the first major televised match card in the location since Hatton's death. As the final chime faded, the quiet gave way to a shout of "only one Ricky Hatton".
The action during the bout reflected the sentiment. The eventual winner was sent to the canvas by a powerful punch directly to the jaw in the initial stage, rising shakily to his feet on the count of eight.
But the Manchester United-red attire of the fighter soon pressed ahead again. Across the ring, Rea - in rival City blue - was marked up early, significant bruising forming under his eye as the duo traded punishing blows.
Rea, 27, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the action hardly diminished over 12 rounds.
The victor barely secured the result with scoring tallies of 114-114, 115-113 and 115-112, but each competitor were determined and courageous, exactly what their idol the legend embodied.
