British light-heavyweight Joshua Buatsi earned a win yet disappointing debut to life under recent management with a points victory over Parker in the Manchester arena.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a competitive 10-round fight at the Manchester venue.
But the challenger found success, landing some telling individual punches in a match where the techniques failed to mesh, with frequent clinching disrupting the fight.
The scoring judges scored it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my finest showing but what defines champions? They win," Buatsi said in the ringside as he was greeted with boos from the spectators.
The Londoner got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to claim a twentieth professional win.
Several boxing experts thought the challenger, thirty-one, deserved the decision but the British boxer experienced the second defeat of his 28-bout professional journey.
Buatsi Earns Win in Dull Affair
The fighter's advancement has stalled in recent times through promotional disputes and extended periods of inactivity.
Earlier forecast as the rising talent of British boxing, he now finds himself trying to fulfil that early promise - maybe in what appears to be a ultimate opportunity - under new promotional backing.
He started carefully, with both competitors prepared to take risks in a calculated early stages.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after breaking his hand in the contest, was making just his second fight at light-heavyweight.
By the halfway stage, Parker had stayed in contention, causing problems for Buatsi, who worked behind a tight guard to barely take the more effective rounds.
The audience's tolerance diminished because of frequent holding, with the challenger falling to the floor several times during close exchanges.
The underdog closed well, but several stanzas were hard to judge. However, former world champion the boxing analyst - commentating on the broadcast network - had it particularly wide for Parker, giving Buatsi just a single round.
Buatsi moves on, but with the presence of hard hitter David Benavidez, and Russian star Bivol ruling the division, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Tribute Motivates Manchester Derby Fight
In the supporting bout, Lyndon Arthur beat Rea by split-decision in a excellent all-Manchester contest to secure the continental belt.
The venue fell silent for a deeply poignant homage ahead of the contest as ten bells rang in remembrance of the city's native Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast match card in the location since Hatton's passing. As the concluding sound disappeared, the silence became a roar of "there's just one Ricky Hatton".
The competition during the bout reflected the sentiment. Arthur was knocked down by a significant blow directly to the face in the initial stage, getting up unsteadily to his feet on the eight count.
But the traditional red shorts of the fighter soon came forward again. From the other corner, Rea - in competitive blue - was damaged quickly, heavy swelling forming under his eye as the duo landed hard punches.
Rea, twenty-seven, delivered effective strikes but Arthur, 34, fought fire with fire with stinging uppercuts as the intensity rarely dropped over twelve rounds.
Arthur edged the verdict with judges scorecards of even score, close margin and 115-112, but the two athletes were relentless and full of heart, everything their hero the legend represented.
