British light heavyweight Buatsi secured a victory yet disappointing debut to life under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a majority decision in a tight 10-round contest at the Manchester venue.
But Parker landed significant shots, landing some telling clean blows in a match where the techniques never quite clicked, with frequent clinching marring the action.
The scoring judges scored it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest display but what do champions do? They prevail," Buatsi said in the ringside as he was greeted with boos from the crowd.
The British fighter got back to winning after his maiden career setback - an memorable fight with Callum Smith in last winter - to claim a 20th career victory.
Some ringside observers thought the challenger, thirty-one, merited the decision but the British boxer experienced the second setback of his 28-match career.
The Champion Claims Victory in Slow Affair
His career development has stalled in recent years through promotional disputes and considerable time of inactivity.
Once tipped as the next star of UK boxing, he now finds himself trying to achieve expectations - possibly in what seems like a last chance - under recent support.
He opened tentatively, with the two boxers willing to take risks in a tentative opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury during the bout, was participating in his second appearance at the higher weight class.
By the middle rounds, Parker had made it competitive, making life awkward for the favorite, who utilized a solid defense to edge the more effective rounds.
The crowd's patience decreased because of constant clinching, with the challenger falling to the floor multiple occasions during close exchanges.
The underdog ended stronger, but several stanzas were hard to judge. However, ex-champion the boxing analyst - commentating on Dazn - had it strongly leaning for Parker, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the caliber of power puncher Benavidez, and Russian champion Bivol dominating the weight class, the road to world glory - judging by this showing - still appears challenging.
Hatton Homage Fuels Manchester Derby Battle
In the supporting bout, Lyndon Arthur defeated Bradley Rea by divided decision in a excellent local rivalry battle to secure the continental title.
The arena fell silent for a profoundly moving tribute before the fight as a bell ceremony tolled in memory of Manchester's own Hatton, who died aged 46 in September.
It was the initial significant broadcast boxing event in the urban center since Hatton's passing. As the concluding sound disappeared, the stillness gave way to a roar of "only one Ricky Hatton".
The action inside the ropes equaled the feeling. Arthur was knocked down by a significant blow directly to the chin in the early round, standing uncertainly to his feet on the referee's count.
But the traditional red equipment of the fighter soon pressed ahead again. On the opposite side, the opponent - in rival City blue - was damaged soon, significant bruising appearing under his eye as the duo exchanged powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with powerful upward punches as the intensity rarely dropped over the full distance.
Arthur narrowly won the verdict with scoring tallies of draw, 115-113 and clearer margin, but both fighters were determined and courageous, everything their inspiration Hatton represented.
