UK light-heavyweight Buatsi earned a win yet disappointing debut to life under new promoters with a unanimous decision over Zach Parker in Manchester.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a close ten-round contest at the Manchester venue.
But the challenger landed significant shots, delivering effective clean blows in a match where the techniques never quite clicked, with frequent clinching spoiling the contest.
The officials scored it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my finest display but what defines champions? They prevail," the victor stated in the ringside as he was greeted with disapproval from the spectators.
The Londoner bounced back after his maiden career setback - an memorable fight with his previous opponent in February - to claim a 20th career victory.
Some ringside observers thought Parker, thirty-one, should have been awarded the decision but the contender experienced the second defeat of his 28-match career.
The Champion Secures Win in Dull Affair
His career development has slowed in the past few years through promotional disputes and long spells of lack of fights.
Earlier forecast as the next star of the British fight scene, he now is positioned trying to realize his potential - possibly in what seems like a ultimate opportunity - under fresh management.
He started carefully, with neither fighter prepared to be aggressive in a calculated opening few rounds.
The challenger, whose sole prior loss came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was competing in only his second bout at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, creating difficulties for Buatsi, who utilized a protective stance to barely take the cleaner stanzas.
The crowd's patience diminished amid frequent holding, with the challenger going down various instances during grappling.
The underdog closed well, but many rounds were challenging to assess. However, ex-champion the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
Buatsi advances, but with the presence of power puncher Benavidez, and Russian champion Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Hatton Tribute Motivates Local Rivalry Fight
In the co-main event, Arthur beat Rea by split-decision in a excellent all-Manchester contest to capture the European light-heavyweight championship.
The venue grew hushed for a deeply poignant memorial prior to the bout as 10 bells sounded in honor of local hero Hatton, who passed away at age 46 in September.
It was the first major televised match card in the location since Hatton's passing. As the final chime ended, the stillness transitioned to a chant of "there's just one Hatton".
The action within the ring matched the emotion. The eventual winner was floored by a powerful punch directly to the jaw in the early round, getting up unsteadily to his position on the eight count.
But the Manchester United-red shorts of the fighter soon pressed ahead again. From the other corner, Rea - in opposing blue - was marked up quickly, noticeable damage appearing under his orbital area as the fighters traded powerful shots.
The challenger, twenty-seven, landed power punches but Arthur, 34, fought fire with fire with effective uppercuts as the pace rarely dropped over 12 rounds.
Arthur barely secured the verdict with official scores of 114-114, 115-113 and 115-112, but the two athletes were determined and brave, everything their inspiration the legend embodied.
