UK light-heavyweight Joshua Buatsi earned a win yet disappointing beginning to life under fresh promotional backing with a decision win over Parker in the Manchester arena.
The Olympic medal winner's work rate likely gained him a judges' verdict in a competitive 10-round bout at the Manchester venue.
But the challenger had his moments, connecting with powerful clean blows in a match where the styles never quite clicked, with constant grabbing marring the fight.
The officials judged it 96-94 to the winner, with the final judge a 95-95 draw.
"It wasn't my finest showing but what defines champions? They prevail," Buatsi said in the ringside as he was met by negative reactions from the spectators.
The Londoner returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts thought the challenger, 31, merited the win but the Derbyshire fighter endured the second loss of his 28-match career.
The Champion Secures Triumph in Dull Match
Buatsi's progress has slowed in the past few years through management issues and considerable time of inactivity.
Earlier forecast as the future of UK boxing, he now finds himself trying to fulfil that early promise - possibly in what seems like a last chance - under new promotional backing.
He opened tentatively, with both competitors willing to take risks in a cagey early stages.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at light-heavyweight.
By the fight's midpoint, the underdog had made it competitive, creating difficulties for the favorite, who operated with a solid defense to narrowly win the cleaner stanzas.
The audience's tolerance decreased during regular grabbing, with the challenger falling to the floor various instances during grappling.
Parker ended stronger, but multiple periods were difficult to score. However, previous titleholder the boxing analyst - working with the broadcast network - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of power puncher David Benavidez, and Russian champion Bivol leading the category, the journey to titles - judging by this showing - still seems difficult.
Ricky Hatton Memorial Inspires Local Rivalry Contest
In the secondary fight, Lyndon Arthur overcame Bradley Rea by split-decision in a excellent local rivalry contest to win the European light heavyweight championship.
The venue fell silent for a extremely emotional memorial prior to the bout as ten bells rang in honor of the city's native Hatton, who passed away at age 46 in September.
It was the initial significant broadcast fight night in the urban center since Hatton's passing. As the final chime disappeared, the stillness gave way to a shout of "only one Ricky Hatton".
The fighting during the bout equaled the feeling. The eventual winner was sent to the canvas by a left hook directly to the jaw in the second round, getting up unsteadily to his position on the count of eight.
But the Manchester United-red equipment of Arthur soon pressed ahead again. Across the ring, the opponent - in competitive blue - was damaged quickly, significant bruising appearing under his eye as the duo landed hard punches.
Rea, twenty-seven, landed power punches but Arthur, thirty-four, responded in kind with effective uppercuts as the intensity hardly diminished over the full distance.
The victor barely secured the verdict with official scores of even score, close margin and clearer margin, but the two athletes were determined and full of heart, exactly what their idol Hatton embodied.
