British light-heavyweight Buatsi earned a win yet unimpressive debut to his career under new promoters with a unanimous decision over Zach Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a split decision in a competitive 10-round contest at the boxing arena.
But the challenger found success, landing some telling single shots in a contest where the approaches never quite clicked, with constant grabbing marring the action.
The officials scored it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest showing but how do champions respond? They succeed," the victor said in the arena as he was greeted with disapproval from the spectators.
The Londoner returned to winning ways after his maiden career setback - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Various analysts believed Parker, thirty-one, deserved the decision but the contender suffered the second setback of his 28-fight professional journey.
The Champion Earns Win in Slow Affair
The fighter's advancement has slowed in recent times through promotional disputes and considerable time of inactivity.
Once tipped as the next star of the British fight scene, he now stands trying to fulfil that early promise - maybe in what appears to be a last chance - under recent support.
He opened tentatively, with both competitors willing to overcommit in a cagey initial rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in 2022 after suffering a hand injury in the contest, was participating in his second bout at the higher weight class.
By the halfway stage, Parker had stayed in contention, creating difficulties for the favorite, who worked behind a solid defense to edge the better rounds.
The spectators' acceptance wore thin because of constant clinching, with the challenger slipping to the canvas multiple occasions during clinches.
The underdog ended stronger, but many rounds were difficult to score. Nevertheless, previous titleholder the boxing analyst - providing analysis for the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the presence of hard hitter Benavidez, and Russian star Bivol leading the category, the journey to titles - judging by this showing - still looks steep.
Ricky Hatton Homage Fuels Local Rivalry Fight
In the supporting bout, Lyndon Arthur defeated Rea by close verdict in a excellent local rivalry fight to capture the European light-heavyweight championship.
The stadium grew hushed for a extremely emotional memorial prior to the bout as 10 bells sounded in remembrance of local hero Ricky Hatton, who passed away aged 46 in September.
It was the initial significant broadcast boxing event in the location since Hatton's passing. As the final chime ended, the stillness gave way to a shout of "only one Hatton".
The fighting inside the ropes reflected the feeling. Arthur was floored by a significant blow directly to the chin in the second round, rising shakily to his footing on the referee's count.
But the red-colored equipment of the fighter soon advanced again. Across the ring, Rea - in competitive blue - was damaged soon, heavy swelling developing under his orbital area as the duo landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but the champion, thirty-four, responded in kind with stinging uppercuts as the pace rarely dropped over the full distance.
Arthur barely secured the result with official scores of draw, narrow lead and wider gap, but both fighters were persistent and full of heart, exactly what their inspiration Hatton stood for.
