UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under new promoters with a points victory over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output appeared to earn him a split decision in a close 10-round contest at the Manchester venue.
But Parker landed significant shots, connecting with powerful single shots in a match where the approaches failed to mesh, with constant grabbing marring the contest.
The scoring judges had it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my finest showing but what do champions do? They win," the victor stated in the arena as he was greeted with disapproval from the crowd.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in February - to claim a 20th career victory.
Several boxing experts thought Parker, thirty-one, should have been awarded the victory but the British boxer endured the second setback of his 28-bout professional journey.
Buatsi Secures Win in Dull Encounter
His career development has stalled in recent years through management issues and long spells of lack of fights.
Once tipped as the next star of British boxing, he now is positioned trying to realize his potential - possibly in what appears to be a ultimate opportunity - under fresh management.
He started carefully, with the two boxers ready to take risks in a tentative opening few rounds.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after breaking his hand during the bout, was participating in his second appearance at light heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for the favorite, who utilized a solid defense to narrowly win the better stanzas.
The spectators' acceptance wore thin because of constant clinching, with the challenger falling to the floor multiple occasions during close exchanges.
Parker finished the stronger, but multiple periods were difficult to score. Although, ex-champion Carl Frampton - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
Buatsi progresses, but with the likes of heavy hitter Benavidez, and Russian champion Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Hatton Memorial Motivates All-Manchester Battle
In the secondary fight, Lyndon Arthur beat Bradley Rea by divided decision in a excellent all-Manchester battle to win the European light heavyweight title.
The arena grew hushed for a deeply poignant homage prior to the bout as a bell ceremony sounded in memory of the city's native Ricky Hatton, who succumbed at age 46 in last month.
It was the first major televised fight night in the location since Hatton's passing. As the last bell faded, the stillness transitioned to a shout of "only one Hatton".
The fighting during the bout equaled the emotion. Arthur was floored by a powerful punch squarely on the chin in the initial stage, rising shakily to his position on the referee's count.
But the traditional red attire of the fighter soon pressed ahead again. On the opposite side, Rea - in competitive blue - was marked up soon, significant bruising developing under his orbital area as the fighters exchanged hard punches.
The challenger, 27, landed power punches but the champion, 34, matched the intensity with stinging uppercuts as the action seldom decreased over 12 rounds.
Arthur edged the result with judges scorecards of even score, narrow lead and clearer margin, but both fighters were relentless and full of heart, all the qualities their idol Hatton embodied.
