UK light heavyweight Buatsi secured a victory yet underwhelming debut to his career under recent management with a unanimous decision over Zach Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a split decision in a competitive ten-round bout at the boxing arena.
But the challenger found success, landing some telling individual punches in a match where the styles failed to mesh, with constant grabbing spoiling the action.
Two judges judged it 96-94 for to Buatsi, with the third a 95-95 draw.
"It wasn't my finest display but what defines champions? They prevail," the victor said in the ringside as he was faced disapproval from the crowd.
The Londoner got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to earn a 20th pro success.
Various analysts believed the challenger, 31, merited the decision but the British boxer suffered the second defeat of his 28-match career.
The Champion Earns Victory in Dull Encounter
Buatsi's progress has slowed in the past few years through management issues and extended periods of inactivity.
Once tipped as the future of British boxing, he now is positioned trying to realize his potential - maybe in what seems like a ultimate opportunity - under recent support.
He began cautiously, with both competitors ready to take risks in a tentative opening few rounds.
The challenger, whose sole prior loss came at super-middleweight against his former opponent in two years ago after damaging his hand during the bout, was making just his second fight at light heavyweight.
By the halfway stage, Parker had made it competitive, creating difficulties for Buatsi, who utilized a tight guard to edge the cleaner stanzas.
The spectators' acceptance wore thin during regular grabbing, with Parker falling to the floor multiple occasions during close exchanges.
Parker ended stronger, but several stanzas were hard to judge. Although, ex-champion Carl Frampton - working with Dazn - had it particularly wide for the challenger, scoring for Buatsi just one round.
The victor moves on, but with the likes of heavy hitter David Benavidez, and Russian champion Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Tribute Motivates Local Rivalry Battle
In the co-main event, Lyndon Arthur defeated Bradley Rea by close verdict in a outstanding all-Manchester fight to capture the European light heavyweight title.
The stadium fell silent for a extremely emotional memorial ahead of the contest as a bell ceremony tolled in honor of local hero Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast fight night in the urban center since Hatton's death. As the concluding sound disappeared, the quiet became a roar of "only one Hatton".
The action during the bout equaled the sentiment. Arthur was floored by a left hook directly to the chin in the early round, rising shakily to his feet on the eight count.
But the Manchester United-red attire of Arthur soon pressed ahead again. Across the ring, the opponent - in rival City blue - was injured soon, noticeable damage developing under his orbital area as the duo traded powerful shots.
The challenger, twenty-seven, delivered effective strikes but the champion, 34, responded in kind with stinging uppercuts as the action hardly diminished over the full distance.
Arthur edged the result with scoring tallies of even score, close margin and 115-112, but the two athletes were persistent and courageous, exactly what their inspiration Hatton represented.
