British light heavyweight Buatsi secured a victory yet underwhelming debut to life under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level likely gained him a judges' verdict in a tight 10-round bout at the Co-op Live Arena.
But the challenger found success, delivering effective individual punches in a match where the styles failed to mesh, with excessive holding disrupting the fight.
The scoring judges scored it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my finest showing but how do champions respond? They prevail," the victor stated in the arena as he was met by negative reactions from the crowd.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with his previous opponent in February - to earn a twentieth professional win.
Several boxing experts felt the challenger, thirty-one, should have been awarded the victory but the British boxer experienced the second loss of his 28-bout professional journey.
The Champion Secures Win in Dull Match
The fighter's advancement has plateaued in recent times through contract problems and long spells of inactivity.
Once tipped as the future of the British fight scene, he now stands trying to achieve expectations - possibly in what seems like a final roll of the dice - under recent support.
He began cautiously, with both competitors prepared to be aggressive in a calculated opening few rounds.
Parker, whose only previous defeat came at super middleweight against his former opponent in two years ago after breaking his hand during the bout, was participating in his second appearance at the higher weight class.
By the halfway stage, Parker had stayed in contention, making life awkward for Buatsi, who worked behind a solid defense to narrowly win the cleaner rounds.
The audience's tolerance wore thin amid constant clinching, with Parker falling to the floor multiple occasions during grappling.
Parker closed well, but many rounds were challenging to assess. However, former world champion the boxing analyst - working with the broadcast network - had it strongly leaning for Parker, giving Buatsi just one round.
Buatsi advances, but with the caliber of hard hitter Benavidez, and Russian star Dmitry Bivol dominating the weight class, the path to championship success - on this evidence - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Battle
In the supporting bout, Arthur beat Rea by close verdict in a terrific Manchester vs Manchester battle to win the European light-heavyweight championship.
The venue fell silent for a profoundly moving memorial prior to the bout as ten bells tolled in memory of local hero Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast boxing event in the city since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a shout of "only one Ricky Hatton".
The competition during the bout equaled the feeling. The eventual winner was floored by a significant blow squarely on the chin in the early round, standing uncertainly to his position on the referee's count.
But the red-colored equipment of Arthur soon came forward again. On the opposite side, Rea - in rival City blue - was damaged soon, heavy swelling forming under his orbital area as the duo exchanged hard punches.
Rea, 27, landed power punches but Arthur, 34, fought fire with fire with effective uppercuts as the action hardly diminished over 12 rounds.
The victor narrowly won the result with official scores of even score, narrow lead and 115-112, but both fighters were relentless and brave, everything their idol Hatton embodied.
