UK light-heavyweight Buatsi earned a win yet underwhelming beginning to life under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a split decision in a competitive ten-round fight at the Manchester venue.
But Parker found success, connecting with powerful individual punches in a contest where the approaches failed to mesh, with frequent clinching spoiling the action.
The scoring judges had it 96-94 for to Buatsi, with the third a even score.
"It wasn't my greatest display but what do champions do? They succeed," Buatsi commented in the ring as he was met by boos from the audience.
The Londoner returned to winning ways after his initial pro loss - an epic battle with Callum Smith in last winter - to claim a 20th career victory.
Some ringside observers felt Parker, 31, deserved the victory but the Derbyshire fighter experienced the second loss of his 28-bout professional journey.
The Champion Claims Win in Dull Match
The fighter's advancement has slowed in recent years through management issues and long spells of lack of fights.
Previously predicted as the next star of UK boxing, he now is positioned trying to realize his potential - possibly in what appears to be a last chance - under recent support.
He started carefully, with neither fighter ready to overcommit in a calculated early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in 2022 after damaging his hand mid-fight, was making just his second bout at light-heavyweight.
By the middle rounds, Parker had stayed in contention, causing problems for the favorite, who utilized a solid defense to edge the more effective stanzas.
The crowd's patience diminished because of regular grabbing, with the challenger falling to the floor several times during close exchanges.
The underdog ended stronger, but several stanzas were difficult to score. Although, ex-champion Carl Frampton - working with Dazn - had it strongly leaning for Parker, giving Buatsi just one round.
Buatsi advances, but with the presence of power puncher Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - based on this performance - still seems difficult.
Ricky Hatton Homage Inspires Local Rivalry Fight
In the supporting bout, Arthur beat Rea by close verdict in a excellent Manchester vs Manchester fight to capture the European light-heavyweight belt.
The venue became quiet for a profoundly moving homage before the fight as a bell ceremony tolled in memory of the city's native Hatton, who passed away 46 years old in recently.
It was the first major televised fight night in the urban center since the passing of Hatton. As the last bell disappeared, the silence transitioned to a roar of "there's only one Ricky Hatton".
The fighting inside the ropes matched the emotion. Arthur was knocked down by a left hook directly to the chin in the second round, rising shakily to his footing on the eight count.
But the red-colored equipment of Arthur soon advanced again. Across the ring, Rea - in opposing blue - was marked up quickly, heavy swelling forming under his orbital area as the duo landed powerful shots.
Rea, twenty-seven, connected with strong blows but Arthur, 34, responded in kind with effective uppercuts as the pace seldom decreased over twelve rounds.
The victor edged the verdict with official scores of 114-114, 115-113 and clearer margin, but the two athletes were persistent and brave, exactly what their inspiration the legend represented.
