UK light heavyweight Buatsi secured a victory yet unimpressive beginning to life under fresh promotional backing with a decision win over Zach Parker in Manchester.
The Olympic medal winner's work rate likely gained him a judges' verdict in a competitive ten-round contest at the Manchester venue.
But Parker had his moments, delivering effective clean blows in a match where the approaches didn't complement each other, with frequent clinching spoiling the contest.
The officials judged it 96-94 in favor to Buatsi, with the final judge a 95-95.
"It wasn't my greatest showing but what defines champions? They win," the victor stated in the ring as he was met by boos from the spectators.
The British fighter got back to winning after his first professional defeat - an epic battle with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts felt the challenger, thirty-one, deserved the win but the Derbyshire fighter suffered the second loss of his 28-fight professional journey.
The Champion Secures Triumph in Uneventful Affair
Buatsi's progress has plateaued in recent years through contract problems and long spells of lack of fights.
Earlier forecast as the future of UK boxing, he now is positioned trying to realize his potential - perhaps in what appears to be a last chance - under fresh management.
He started carefully, with both competitors ready to overcommit in a cagey opening few rounds.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in 2022 after breaking his hand during the bout, was competing in only his second bout at the higher weight class.
By the halfway stage, the underdog had made it competitive, making life awkward for the favorite, who utilized a protective stance to edge the cleaner stanzas.
The spectators' acceptance diminished amid regular grabbing, with Parker falling to the floor several times during grappling.
The underdog closed well, but multiple periods were hard to judge. Nevertheless, ex-champion Carl Frampton - working with Dazn - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the likes of heavy hitter Benavidez, and Russian star Dmitry Bivol ruling the division, the journey to titles - based on this performance - still seems difficult.
Ricky Hatton Homage Fuels Local Rivalry Fight
In the co-main event, Lyndon Arthur beat Bradley Rea by divided decision in a outstanding local rivalry fight to secure the continental championship.
The venue fell silent for a profoundly moving homage ahead of the contest as ten bells sounded in memory of local hero Hatton, who succumbed 46 years old in recently.
It was the initial significant broadcast fight night in the location since Hatton's passing. As the last bell faded, the silence became a shout of "there's only one Hatton".
The fighting inside the ropes equaled the feeling. The eventual winner was sent to the canvas by a left hook squarely on the jaw in the second round, standing uncertainly to his footing on the referee's count.
But the red-colored equipment of the fighter soon advanced again. Across the ring, Rea - in rival City blue - was damaged early, noticeable damage developing under his face as the duo traded hard punches.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with powerful upward punches as the action hardly diminished over 12 rounds.
The victor narrowly won the verdict with judges scorecards of even score, narrow lead and wider gap, but the two athletes were persistent and full of heart, all the qualities their idol Hatton stood for.
