British light heavyweight Buatsi earned a win yet disappointing debut to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a majority decision in a tight 10-round contest at the Manchester venue.
But the challenger had his moments, delivering effective clean blows in a contest where the techniques never quite clicked, with constant grabbing marring the action.
Two judges judged it 96-94 to the winner, with the remaining official a 95-95 draw.
"It wasn't my greatest showing but how do champions respond? They win," Buatsi stated in the ringside as he was faced disapproval from the audience.
The Londoner returned to winning ways after his initial pro loss - an epic battle with his previous opponent in last winter - to claim a 20th career victory.
Various analysts felt Parker, thirty-one, should have been awarded the win but the British boxer suffered the second defeat of his 28-match career.
The Champion Secures Victory in Uneventful Encounter
Buatsi's progress has stalled in recent times through management issues and extended periods of inactivity.
Earlier forecast as the rising talent of British boxing, he now finds himself trying to achieve expectations - maybe in what feels like a final roll of the dice - under recent support.
He started carefully, with neither fighter willing to overcommit in a cagey early stages.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in two years ago after breaking his hand during the bout, was competing in only his second bout at light-heavyweight.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who worked behind a solid defense to barely take the cleaner periods.
The audience's tolerance wore thin amid regular grabbing, with Parker slipping to the canvas several times during grappling.
The underdog closed well, but several stanzas were challenging to assess. However, former world champion Carl Frampton - providing analysis for Dazn - had it particularly wide for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still seems difficult.
Hatton Homage Motivates Manchester Derby Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by close verdict in a excellent local rivalry fight to secure the European light heavyweight belt.
The venue became quiet for a profoundly moving memorial ahead of the contest as 10 bells tolled in remembrance of Manchester's own Hatton, who died aged 46 in last month.
It was the first major televised fight night in the city since Hatton's death. As the concluding sound faded, the silence gave way to a roar of "only one Hatton".
The competition inside the ropes equaled the emotion. The eventual winner was sent to the canvas by a left hook directly to the jaw in the early round, rising shakily to his feet on the eight count.
But the Manchester United-red shorts of Arthur soon came forward again. Across the ring, Rea - in rival City blue - was damaged quickly, heavy swelling developing under his orbital area as the pair exchanged hard punches.
The challenger, twenty-seven, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the action rarely dropped over the full distance.
The victor barely secured the verdict with official scores of draw, narrow lead and 115-112, but both fighters were persistent and brave, all the qualities their idol Hatton embodied.
