UK light-heavyweight Buatsi earned a win yet unimpressive beginning to life under fresh promotional backing with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a competitive ten-round bout at the Manchester venue.
But the challenger found success, landing some telling clean blows in a contest where the styles failed to mesh, with frequent clinching spoiling the action.
The officials scored it 96-94 in favor to the winner, with the remaining official a 95-95 draw.
"It wasn't my best performance but what defines champions? They succeed," the victor commented in the ring as he was faced disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Several boxing experts believed the challenger, thirty-one, merited the win but the contender endured the second setback of his 28-match career.
Buatsi Claims Triumph in Slow Encounter
The fighter's advancement has slowed in the past few years through management issues and extended periods of inactivity.
Earlier forecast as the next star of British boxing, he now stands trying to realize his potential - maybe in what seems like a final roll of the dice - under new promotional backing.
He opened tentatively, with both competitors ready to be aggressive in a calculated opening few rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury in the contest, was making just his second fight at light heavyweight.
By the middle rounds, Parker had kept it close, making life awkward for the favorite, who utilized a protective stance to narrowly win the cleaner rounds.
The crowd's patience wore thin because of frequent holding, with Parker falling to the floor various instances during grappling.
The underdog finished the stronger, but several stanzas were hard to judge. However, former world champion the boxing analyst - working with the broadcast network - had it particularly wide for Parker, scoring for Buatsi just only one stanza.
The victor moves on, but with the presence of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Hatton Homage Fuels Manchester Derby Contest
In the secondary fight, Arthur overcame Bradley Rea by close verdict in a excellent Manchester vs Manchester fight to capture the European light-heavyweight belt.
The stadium grew hushed for a profoundly moving homage ahead of the contest as ten bells tolled in remembrance of local hero Ricky Hatton, who succumbed at age 46 in September.
It was the premier televised boxing event in the location since Hatton's death. As the last bell disappeared, the silence gave way to a shout of "only one Ricky Hatton".
The competition inside the ropes equaled the sentiment. Arthur was floored by a significant blow directly to the chin in the second round, standing uncertainly to his position on the eight count.
But the Manchester United-red equipment of Arthur soon advanced again. On the opposite side, the opponent - in competitive blue - was damaged quickly, heavy swelling appearing under his orbital area as the fighters traded powerful shots.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, matched the intensity with stinging uppercuts as the intensity rarely dropped over the full distance.
The victor narrowly won the decision with official scores of 114-114, 115-113 and clearer margin, but both fighters were determined and brave, exactly what their idol the legend represented.
