British light-heavyweight Buatsi made a winning yet underwhelming debut to life under recent management with a decision win over Zach Parker in Manchester.
The Olympic bronze medallist's activity level likely gained him a majority decision in a competitive 10-round fight at the Manchester venue.
But the challenger had his moments, delivering effective single shots in a match where the techniques never quite clicked, with frequent clinching marring the contest.
The officials scored it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my finest performance but what do champions do? They succeed," Buatsi said in the ringside as he was met by negative reactions from the crowd.
The Londoner bounced back after his maiden career setback - an thrilling contest with his previous opponent in last winter - to earn a 20th career victory.
Various analysts thought Parker, 31, deserved the decision but the Derbyshire fighter endured the second defeat of his 28-match career.
The Champion Earns Victory in Slow Match
The fighter's advancement has slowed in recent times through promotional disputes and considerable time of inactivity.
Earlier forecast as the rising talent of British boxing, he now finds himself trying to achieve expectations - maybe in what seems like a ultimate opportunity - under fresh management.
He opened tentatively, with both competitors willing to take risks in a tentative initial rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after suffering a hand injury during the bout, was making just his second bout at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for Buatsi, who operated with a solid defense to barely take the more effective stanzas.
The audience's tolerance diminished amid frequent holding, with the challenger slipping to the canvas several times during grappling.
The underdog finished the stronger, but many rounds were hard to judge. However, previous titleholder Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
The victor moves on, but with the caliber of heavy hitter Benavidez, and Eastern European fighter Bivol leading the category, the journey to titles - based on this performance - still seems difficult.
Hatton Tribute Inspires Local Rivalry Contest
In the supporting bout, Arthur overcame Rea by split-decision in a terrific Manchester vs Manchester contest to secure the European light heavyweight title.
The arena grew hushed for a profoundly moving tribute ahead of the contest as ten bells rang in remembrance of Manchester's own Hatton, who passed away aged 46 in last month.
It was the premier televised boxing event in the urban center since Hatton's passing. As the final chime ended, the stillness transitioned to a chant of "only one Ricky Hatton".
The action during the bout matched the emotion. The eventual winner was knocked down by a significant blow squarely on the face in the early round, rising shakily to his feet on the eight count.
But the traditional red equipment of Arthur soon advanced again. From the other corner, the opponent - in rival City blue - was damaged soon, significant bruising developing under his orbital area as the pair traded punishing blows.
Rea, 27, landed power punches but Arthur, 34, responded in kind with effective uppercuts as the pace seldom decreased over 12 rounds.
The victor barely secured the decision with official scores of 114-114, 115-113 and clearer margin, but the two athletes were determined and courageous, everything their inspiration the legend stood for.
