UK light heavyweight Joshua Buatsi made a winning yet disappointing beginning to his career under fresh promotional backing with a decision win over Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a split decision in a competitive ten-round bout at the boxing arena.
But Parker found success, delivering effective single shots in a contest where the techniques didn't complement each other, with frequent clinching marring the contest.
The scoring judges judged it 96-94 for to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest showing but what defines champions? They succeed," Buatsi stated in the ringside as he was faced disapproval from the spectators.
The Londoner got back to winning after his maiden career setback - an memorable fight with his previous opponent in last winter - to secure a 20th career victory.
Various analysts felt the challenger, 31, deserved the decision but the Derbyshire fighter experienced the second defeat of his 28-fight professional journey.
Buatsi Earns Victory in Uneventful Encounter
The fighter's advancement has plateaued in recent times through management issues and extended periods of inactivity.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to achieve expectations - possibly in what feels like a final roll of the dice - under new promotional backing.
He started carefully, with the two boxers ready to take risks in a cagey early stages.
The challenger, whose sole prior loss came at super middleweight against his former opponent in 2022 after suffering a hand injury mid-fight, was participating in his second bout at light heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for the favorite, who worked behind a protective stance to barely take the more effective rounds.
The audience's tolerance diminished amid constant clinching, with Parker falling to the floor multiple occasions during grappling.
Parker finished the stronger, but many rounds were challenging to assess. Although, former world champion Carl Frampton - commentating on Dazn - had it particularly wide for Parker, awarding Buatsi just a single round.
The victor progresses, but with the caliber of heavy hitter David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Ricky Hatton Homage Inspires Local Rivalry Contest
In the supporting bout, Lyndon Arthur beat Bradley Rea by close verdict in a outstanding local rivalry fight to win the continental championship.
The stadium fell silent for a extremely emotional memorial prior to the bout as 10 bells tolled in remembrance of local hero Hatton, who succumbed aged 46 in September.
It was the premier televised match card in the location since the passing of Hatton. As the concluding sound disappeared, the quiet transitioned to a chant of "there's only one Hatton".
The competition during the bout matched the feeling. The eventual winner was floored by a significant blow flush on the jaw in the second round, getting up unsteadily to his position on the referee's count.
But the traditional red shorts of Arthur soon came forward again. Across the ring, the opponent - in rival City blue - was marked up early, significant bruising forming under his eye as the pair exchanged hard punches.
Rea, 27, delivered effective strikes but the champion, 34, responded in kind with stinging uppercuts as the intensity seldom decreased over the full distance.
The victor barely secured the result with scoring tallies of draw, narrow lead and wider gap, but each competitor were persistent and brave, all the qualities their inspiration Hatton embodied.
