British light-heavyweight Buatsi made a winning yet unimpressive beginning to his career under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's work rate appeared to earn him a majority decision in a competitive ten-round fight at the boxing arena.
But Parker had his moments, connecting with powerful individual punches in a fight where the styles didn't complement each other, with frequent clinching spoiling the contest.
The scoring judges had it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my best display but what do champions do? They win," Buatsi commented in the ringside as he was faced boos from the crowd.
The British fighter returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in last winter - to earn a 20th pro success.
Several boxing experts felt the challenger, thirty-one, deserved the win but the contender endured the second setback of his 28-match career.
The Champion Earns Victory in Slow Encounter
His career development has stalled in recent times through management issues and extended periods of lack of fights.
Earlier forecast as the future of the British fight scene, he now stands trying to realize his potential - perhaps in what appears to be a final roll of the dice - under new promotional backing.
He started carefully, with neither fighter willing to overcommit in a cagey early stages.
The challenger, whose sole prior loss came at the lower weight class against John Ryder in two years ago after damaging his hand mid-fight, was competing in only his second appearance at light heavyweight.
By the halfway stage, Parker had stayed in contention, causing problems for Buatsi, who utilized a solid defense to barely take the better rounds.
The audience's tolerance decreased amid constant clinching, with Parker slipping to the canvas various instances during grappling.
Parker ended stronger, but several stanzas were difficult to score. However, previous titleholder the boxing analyst - providing analysis for Dazn - had it significantly in favor for Parker, scoring for Buatsi just one round.
Buatsi progresses, but with the presence of power puncher Benavidez, and Russian champion Dmitry Bivol leading the category, the road to world glory - judging by this showing - still appears challenging.
Ricky Hatton Memorial Inspires Manchester Derby Fight
In the co-main event, Lyndon Arthur overcame Bradley Rea by divided decision in a outstanding Manchester vs Manchester fight to win the continental belt.
The venue grew hushed for a profoundly moving homage ahead of the contest as ten bells rang in remembrance of Manchester's own Hatton, who passed away at age 46 in recently.
It was the premier televised match card in the location since Hatton's death. As the concluding sound ended, the quiet gave way to a shout of "there's only one Ricky Hatton".
The action within the ring equaled the emotion. Arthur was knocked down by a significant blow squarely on the face in the initial stage, standing uncertainly to his feet on the count of eight.
But the Manchester United-red shorts of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was injured soon, heavy swelling forming under his orbital area as the fighters traded punishing blows.
Rea, twenty-seven, landed power punches but Arthur, 34, matched the intensity with effective uppercuts as the action seldom decreased over 12 rounds.
The victor edged the verdict with official scores of draw, narrow lead and 115-112, but both fighters were determined and courageous, all the qualities their hero the legend embodied.
