British light-heavyweight Buatsi earned a win yet disappointing debut to his career under new promoters with a decision win over Zach Parker in the Manchester arena.
The Olympic medal winner's punch output likely gained him a judges' verdict in a tight 10-round bout at the boxing arena.
But the challenger found success, landing some telling clean blows in a match where the styles never quite clicked, with constant grabbing marring the contest.
Two judges scored it 96-94 in favor to the winner, with the third a 95-95.
"It wasn't my greatest performance but what defines champions? They succeed," the victor commented in the ring as he was faced negative reactions from the audience.
The Londoner got back to winning after his first professional defeat - an thrilling contest with Callum Smith in February - to claim a 20th pro success.
Various analysts felt the challenger, 31, should have been awarded the decision but the contender suffered the second setback of his 28-bout career.
The Champion Secures Victory in Slow Affair
His career development has plateaued in recent times through contract problems and considerable time of inactivity.
Previously predicted as the future of British boxing, he now is positioned trying to fulfil that early promise - perhaps in what seems like a ultimate opportunity - under fresh management.
He started carefully, with the two boxers ready to overcommit in a cagey early stages.
Parker, whose sole prior loss came at the lower weight class against his former opponent in 2022 after suffering a hand injury mid-fight, was participating in his second appearance at light heavyweight.
By the halfway stage, the underdog had kept it close, creating difficulties for Buatsi, who operated with a tight guard to edge the cleaner periods.
The crowd's patience diminished during frequent holding, with Parker falling to the floor various instances during close exchanges.
The underdog ended stronger, but several stanzas were challenging to assess. However, previous titleholder Carl Frampton - working with the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
The victor moves on, but with the caliber of power puncher Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Ricky Hatton Tribute Fuels Local Rivalry Fight
In the supporting bout, Lyndon Arthur beat Bradley Rea by close verdict in a outstanding all-Manchester battle to secure the continental belt.
The stadium grew hushed for a deeply poignant tribute ahead of the contest as 10 bells rang in honor of local hero Hatton, who succumbed at age 46 in recently.
It was the initial significant broadcast fight night in the urban center since the passing of Hatton. As the final chime ended, the silence gave way to a shout of "only one Ricky Hatton".
The fighting inside the ropes equaled the sentiment. The eventual winner was floored by a left hook squarely on the chin in the second round, standing uncertainly to his feet on the referee's count.
But the red-colored equipment of Arthur soon advanced again. On the opposite side, Rea - in opposing blue - was injured early, significant bruising developing under his orbital area as the duo exchanged powerful shots.
Rea, 27, landed power punches but the champion, thirty-four, matched the intensity with stinging uppercuts as the intensity hardly diminished over the full distance.
The victor barely secured the result with judges scorecards of even score, close margin and wider gap, but each competitor were persistent and full of heart, exactly what their inspiration the legend embodied.
