UK light heavyweight Buatsi earned a win yet disappointing beginning to life under new promoters with a points victory over Zach Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a close ten-round contest at the Co-op Live Arena.
But the challenger had his moments, landing some telling clean blows in a match where the techniques didn't complement each other, with constant grabbing spoiling the action.
The scoring judges judged it 96-94 for to Buatsi, with the remaining official a even score.
"It wasn't my best performance but what do champions do? They succeed," Buatsi said in the ring as he was greeted with disapproval from the spectators.
The British fighter bounced back after his first professional defeat - an thrilling contest with his previous opponent in last winter - to secure a twentieth professional win.
Various analysts believed Parker, 31, should have been awarded the decision but the Derbyshire fighter suffered the second setback of his 28-bout career.
The Champion Secures Victory in Uneventful Affair
The fighter's advancement has stalled in the past few years through promotional disputes and long spells of inactivity.
Earlier forecast as the rising talent of British boxing, he now stands trying to achieve expectations - perhaps in what feels like a final roll of the dice - under fresh management.
He began cautiously, with neither fighter willing to take risks in a tentative initial rounds.
The challenger, whose only previous defeat came at super-middleweight against John Ryder in two years ago after damaging his hand mid-fight, was participating in his second fight at the higher weight class.
By the middle rounds, Parker had made it competitive, creating difficulties for the favorite, who utilized a solid defense to edge the better rounds.
The spectators' acceptance diminished amid constant clinching, with Parker going down several times during clinches.
The underdog closed well, but many rounds were hard to judge. Although, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Russian champion Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Memorial Inspires All-Manchester Fight
In the co-main event, Arthur defeated Rea by split-decision in a excellent local rivalry contest to win the European light-heavyweight championship.
The arena grew hushed for a deeply poignant memorial before the fight as 10 bells rang in honor of Manchester's own Ricky Hatton, who died aged 46 in September.
It was the initial significant broadcast fight night in the location since the passing of Hatton. As the last bell faded, the silence transitioned to a chant of "there's only one Ricky Hatton".
The fighting within the ring reflected the feeling. Arthur was knocked down by a significant blow directly to the face in the second round, getting up unsteadily to his feet on the referee's count.
But the traditional red attire of Arthur soon advanced again. From the other corner, the opponent - in competitive blue - was injured soon, significant bruising developing under his eye as the fighters exchanged hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the pace rarely dropped over 12 rounds.
The victor narrowly won the result with judges scorecards of draw, 115-113 and wider gap, but the two athletes were relentless and brave, exactly what their hero the legend embodied.
