UK light heavyweight Buatsi secured a victory yet disappointing beginning to his career under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a competitive ten-round bout at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful clean blows in a fight where the styles didn't complement each other, with constant grabbing spoiling the contest.
The scoring judges judged it 96-94 in favor to Buatsi, with the third a 95-95 draw.
"It wasn't my finest performance but how do champions respond? They succeed," the victor said in the ring as he was met by boos from the crowd.
The Londoner returned to winning ways after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th pro success.
Some ringside observers felt the challenger, thirty-one, should have been awarded the victory but the contender endured the second loss of his 28-fight career.
The Champion Secures Win in Uneventful Affair
The fighter's advancement has stalled in recent years through management issues and considerable time of inactivity.
Previously predicted as the rising talent of the British fight scene, he now is positioned trying to achieve expectations - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter ready to take risks in a tentative initial rounds.
Parker, whose sole prior loss came at super middleweight against his former opponent in 2022 after breaking his hand during the bout, was competing in only his second bout at light-heavyweight.
By the halfway stage, the underdog had kept it close, making life awkward for Buatsi, who utilized a solid defense to narrowly win the more effective periods.
The audience's tolerance wore thin during constant clinching, with Parker going down several times during grappling.
The underdog closed well, but several stanzas were difficult to score. However, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it particularly wide for Parker, scoring for Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the road to world glory - judging by this showing - still looks steep.
Hatton Homage Inspires Local Rivalry Fight
In the secondary fight, Lyndon Arthur beat Bradley Rea by close verdict in a terrific local rivalry contest to capture the European light-heavyweight championship.
The stadium grew hushed for a profoundly moving homage ahead of the contest as a bell ceremony tolled in remembrance of local hero Hatton, who passed away 46 years old in September.
It was the initial significant broadcast boxing event in the urban center since Hatton's death. As the concluding sound disappeared, the silence gave way to a chant of "there's only one Hatton".
The fighting during the bout reflected the sentiment. Arthur was knocked down by a left hook squarely on the chin in the second round, standing uncertainly to his footing on the referee's count.
But the Manchester United-red equipment of Arthur soon advanced again. On the opposite side, Rea - in competitive blue - was damaged quickly, heavy swelling forming under his orbital area as the duo landed hard punches.
Rea, 27, delivered effective strikes but the champion, thirty-four, responded in kind with stinging uppercuts as the pace rarely dropped over 12 rounds.
The victor narrowly won the decision with judges scorecards of draw, close margin and wider gap, but the two athletes were relentless and courageous, exactly what their idol Hatton embodied.
