British light heavyweight Joshua Buatsi earned a win yet disappointing debut to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's work rate likely gained him a majority decision in a close ten-round contest at the boxing arena.
But the challenger landed significant shots, connecting with powerful single shots in a match where the techniques never quite clicked, with frequent clinching spoiling the action.
The officials scored it 96-94 for to the winner, with the third a 95-95 draw.
"It wasn't my greatest display but what do champions do? They win," Buatsi stated in the arena as he was greeted with disapproval from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in February - to claim a 20th career victory.
Various analysts believed the challenger, 31, should have been awarded the win but the contender endured the second loss of his 28-bout career.
The Champion Claims Victory in Uneventful Match
His career development has stalled in recent times through management issues and extended periods of lack of fights.
Earlier forecast as the rising talent of British boxing, he now finds himself trying to achieve expectations - possibly in what seems like a final roll of the dice - under recent support.
He began cautiously, with neither fighter ready to be aggressive in a calculated initial rounds.
Parker, whose only previous defeat came at the lower weight class against his former opponent in two years ago after damaging his hand in the contest, was competing in only his second bout at the higher weight class.
By the halfway stage, Parker had made it competitive, causing problems for the favorite, who utilized a tight guard to edge the cleaner rounds.
The spectators' acceptance wore thin during frequent holding, with the challenger slipping to the canvas various instances during close exchanges.
The underdog finished the stronger, but several stanzas were challenging to assess. However, former world champion Carl Frampton - working with the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
The victor moves on, but with the presence of heavy hitter David Benavidez, and Russian star Bivol ruling the division, the path to championship success - on this evidence - still appears challenging.
Ricky Hatton Homage Motivates Manchester Derby Contest
In the supporting bout, Lyndon Arthur overcame Bradley Rea by divided decision in a excellent local rivalry battle to win the European light-heavyweight championship.
The arena became quiet for a extremely emotional homage before the fight as 10 bells tolled in honor of Manchester's own Ricky Hatton, who died 46 years old in last month.
It was the first major televised boxing event in the city since Hatton's death. As the concluding sound ended, the stillness became a chant of "only one Hatton".
The action during the bout matched the sentiment. The eventual winner was floored by a powerful punch directly to the chin in the second round, standing uncertainly to his footing on the referee's count.
But the traditional red attire of Arthur soon came forward again. Across the ring, Rea - in rival City blue - was damaged soon, significant bruising forming under his face as the duo traded punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, responded in kind with effective uppercuts as the pace hardly diminished over 12 rounds.
The victor barely secured the decision with judges scorecards of 114-114, 115-113 and clearer margin, but each competitor were persistent and full of heart, all the qualities their hero the legend embodied.
