British light heavyweight Joshua Buatsi made a winning yet underwhelming start to life under recent management with a points victory over Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a close ten-round contest at the boxing arena.
But Parker had his moments, landing some telling clean blows in a match where the styles didn't complement each other, with constant grabbing disrupting the action.
The officials scored it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my best performance but what do champions do? They win," the victor said in the ring as he was met by disapproval from the audience.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Some ringside observers thought Parker, thirty-one, merited the decision but the Derbyshire fighter suffered the second loss of his 28-bout professional journey.
Buatsi Secures Triumph in Uneventful Match
The fighter's advancement has stalled in the past few years through promotional disputes and considerable time of inactivity.
Earlier forecast as the rising talent of British boxing, he now stands trying to achieve expectations - perhaps in what seems like a ultimate opportunity - under recent support.
He began cautiously, with the two boxers ready to overcommit in a cagey opening few rounds.
Parker, whose single earlier setback came at super-middleweight against his former opponent in 2022 after damaging his hand mid-fight, was making just his second appearance at light-heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for the favorite, who utilized a protective stance to narrowly win the better rounds.
The spectators' acceptance decreased during regular grabbing, with the challenger slipping to the canvas various instances during close exchanges.
The underdog closed well, but multiple periods were difficult to score. Nevertheless, ex-champion the boxing analyst - providing analysis for the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the road to world glory - on this evidence - still seems difficult.
Hatton Tribute Fuels All-Manchester Fight
In the secondary fight, Lyndon Arthur defeated Rea by divided decision in a excellent local rivalry fight to secure the European light heavyweight belt.
The stadium fell silent for a deeply poignant tribute before the fight as 10 bells tolled in honor of local hero Ricky Hatton, who succumbed aged 46 in last month.
It was the premier televised fight night in the location since Hatton's passing. As the final chime disappeared, the quiet became a shout of "there's only one Hatton".
The competition inside the ropes reflected the feeling. The eventual winner was floored by a powerful punch directly to the chin in the early round, standing uncertainly to his feet on the referee's count.
But the traditional red equipment of Arthur soon pressed ahead again. On the opposite side, Rea - in competitive blue - was marked up early, heavy swelling appearing under his eye as the duo landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but the champion, 34, fought fire with fire with effective uppercuts as the pace rarely dropped over the full distance.
Arthur barely secured the verdict with scoring tallies of 114-114, close margin and clearer margin, but each competitor were determined and brave, exactly what their idol the legend embodied.
