British light heavyweight Buatsi secured a victory yet unimpressive beginning to life under fresh promotional backing with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's activity level likely gained him a majority decision in a tight 10-round contest at the Co-op Live Arena.
But Parker had his moments, connecting with powerful single shots in a fight where the approaches never quite clicked, with frequent clinching spoiling the fight.
The officials had it 96-94 to the winner, with the third a 95-95 draw.
"It wasn't my best performance but what do champions do? They win," the victor commented in the ring as he was faced disapproval from the spectators.
The Londoner got back to winning after his maiden career setback - an memorable fight with Callum Smith in last winter - to earn a 20th career victory.
Several boxing experts believed Parker, 31, deserved the win but the British boxer endured the second loss of his 28-bout career.
Buatsi Earns Victory in Slow Affair
The fighter's advancement has plateaued in recent years through promotional disputes and considerable time of inactivity.
Earlier forecast as the rising talent of British boxing, he now is positioned trying to realize his potential - perhaps in what appears to be a ultimate opportunity - under fresh management.
He began cautiously, with the two boxers prepared to overcommit in a tentative initial rounds.
The challenger, whose sole prior loss came at super-middleweight against John Ryder in 2022 after damaging his hand during the bout, was making just his second fight at light-heavyweight.
By the middle rounds, the underdog had made it competitive, causing problems for the favorite, who operated with a solid defense to edge the cleaner rounds.
The crowd's patience decreased amid regular grabbing, with Parker slipping to the canvas various instances during close exchanges.
Parker closed well, but many rounds were challenging to assess. Although, previous titleholder Carl Frampton - providing analysis for the broadcast network - had it significantly in favor for the challenger, giving Buatsi just a single round.
The victor advances, but with the likes of heavy hitter Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Memorial Inspires Local Rivalry Contest
In the secondary fight, Lyndon Arthur defeated Rea by split-decision in a terrific Manchester vs Manchester fight to win the European light heavyweight belt.
The venue became quiet for a profoundly moving homage ahead of the contest as a bell ceremony tolled in honor of the city's native Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast boxing event in the location since Hatton's death. As the final chime faded, the silence became a shout of "there's just one Ricky Hatton".
The competition during the bout equaled the sentiment. Arthur was sent to the canvas by a significant blow directly to the jaw in the initial stage, rising shakily to his footing on the eight count.
But the red-colored attire of the fighter soon came forward again. On the opposite side, Rea - in opposing blue - was injured early, noticeable damage developing under his eye as the pair exchanged hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, matched the intensity with effective uppercuts as the pace rarely dropped over the full distance.
The victor narrowly won the result with official scores of draw, close margin and wider gap, but each competitor were determined and full of heart, everything their idol the legend embodied.
