UK light-heavyweight Buatsi earned a win yet disappointing beginning to his career under fresh promotional backing with a points victory over Zach Parker in Manchester.
The Olympic medal winner's punch output likely gained him a majority decision in a tight ten-round contest at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a contest where the styles never quite clicked, with constant grabbing disrupting the action.
The scoring judges scored it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my finest display but how do champions respond? They win," the victor stated in the ring as he was faced boos from the audience.
The Londoner got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to secure a 20th career victory.
Some ringside observers felt Parker, thirty-one, should have been awarded the decision but the British boxer experienced the second defeat of his 28-fight professional journey.
Buatsi Secures Victory in Dull Affair
His career development has slowed in recent years through contract problems and extended periods of inactivity.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what appears to be a final roll of the dice - under fresh management.
He began cautiously, with neither fighter ready to overcommit in a calculated initial rounds.
Parker, whose sole prior loss came at super middleweight against John Ryder in 2022 after breaking his hand mid-fight, was participating in his second appearance at light-heavyweight.
By the halfway stage, Parker had kept it close, causing problems for Buatsi, who utilized a protective stance to narrowly win the better rounds.
The audience's tolerance decreased because of constant clinching, with the challenger slipping to the canvas several times during clinches.
The underdog finished the stronger, but several stanzas were challenging to assess. However, previous titleholder the boxing analyst - working with the broadcast network - had it strongly leaning for Parker, awarding Buatsi just only one stanza.
The victor progresses, but with the likes of power puncher Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the path to championship success - judging by this showing - still seems difficult.
Hatton Tribute Inspires All-Manchester Fight
In the secondary fight, Arthur beat Bradley Rea by split-decision in a terrific all-Manchester battle to win the European light-heavyweight belt.
The arena grew hushed for a profoundly moving tribute ahead of the contest as 10 bells rang in remembrance of the city's native Ricky Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast fight night in the urban center since Hatton's death. As the last bell faded, the silence gave way to a chant of "only one Hatton".
The action within the ring matched the sentiment. The eventual winner was knocked down by a left hook directly to the jaw in the early round, standing uncertainly to his footing on the count of eight.
But the Manchester United-red equipment of Arthur soon came forward again. From the other corner, the opponent - in competitive blue - was injured soon, heavy swelling developing under his face as the pair landed punishing blows.
The challenger, 27, delivered effective strikes but the champion, thirty-four, fought fire with fire with effective uppercuts as the intensity seldom decreased over 12 rounds.
The victor narrowly won the verdict with official scores of draw, 115-113 and clearer margin, but each competitor were determined and full of heart, all the qualities their inspiration the legend represented.
