UK light heavyweight Buatsi made a winning yet disappointing debut to his career under recent management with a points victory over Zach Parker in Manchester.
The Olympic medal winner's activity level appeared to earn him a majority decision in a tight 10-round bout at the Manchester venue.
But Parker found success, connecting with powerful clean blows in a fight where the approaches didn't complement each other, with excessive holding disrupting the contest.
The officials scored it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my finest performance but what do champions do? They prevail," Buatsi commented in the ringside as he was greeted with boos from the crowd.
The British fighter got back to winning after his initial pro loss - an epic battle with his previous opponent in February - to claim a twentieth professional win.
Various analysts felt the challenger, 31, merited the decision but the British boxer endured the second loss of his 28-match professional journey.
The Champion Claims Triumph in Uneventful Match
Buatsi's progress has plateaued in recent times through management issues and considerable time of lack of fights.
Earlier forecast as the next star of the British fight scene, he now is positioned trying to fulfil that early promise - maybe in what feels like a final roll of the dice - under fresh management.
He began cautiously, with the two boxers willing to overcommit in a cagey opening few rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in 2022 after breaking his hand mid-fight, was participating in his second fight at light heavyweight.
By the middle rounds, Parker had kept it close, creating difficulties for Buatsi, who worked behind a tight guard to narrowly win the better rounds.
The spectators' acceptance wore thin because of constant clinching, with Parker falling to the floor multiple occasions during grappling.
The underdog finished the stronger, but many rounds were hard to judge. However, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just a single round.
The victor moves on, but with the presence of hard hitter David Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - judging by this showing - still seems difficult.
Hatton Tribute Motivates Local Rivalry Fight
In the co-main event, Lyndon Arthur beat Rea by divided decision in a terrific all-Manchester battle to win the continental championship.
The venue fell silent for a deeply poignant homage ahead of the contest as ten bells rang in memory of the city's native Hatton, who passed away at age 46 in September.
It was the premier televised fight night in the location since Hatton's passing. As the final chime disappeared, the silence became a roar of "there's just one Ricky Hatton".
The action during the bout equaled the sentiment. Arthur was floored by a powerful punch flush on the face in the early round, getting up unsteadily to his position on the referee's count.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, the opponent - in competitive blue - was injured early, noticeable damage developing under his eye as the fighters traded hard punches.
Rea, 27, landed power punches but the champion, thirty-four, fought fire with fire with effective uppercuts as the action rarely dropped over the full distance.
The victor barely secured the decision with judges scorecards of draw, 115-113 and 115-112, but the two athletes were persistent and full of heart, everything their hero Hatton represented.
