UK light heavyweight Joshua Buatsi made a winning yet disappointing start to his career under fresh promotional backing with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's work rate seemingly secured him a majority decision in a close ten-round contest at the Manchester venue.
But Parker found success, delivering effective individual punches in a contest where the approaches didn't complement each other, with constant grabbing disrupting the action.
Two judges judged it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my greatest performance but what do champions do? They prevail," the victor commented in the ringside as he was faced boos from the audience.
The British fighter got back to winning after his first professional defeat - an thrilling contest with his previous opponent in February - to claim a 20th career victory.
Various analysts believed Parker, 31, merited the victory but the contender endured the second setback of his 28-match professional journey.
Buatsi Earns Win in Dull Match
His career development has plateaued in the past few years through promotional disputes and extended periods of inactivity.
Earlier forecast as the next star of the British fight scene, he now finds himself trying to realize his potential - possibly in what feels like a final roll of the dice - under new promotional backing.
He began cautiously, with both competitors ready to take risks in a tentative early stages.
The challenger, whose only previous defeat came at the lower weight class against John Ryder in two years ago after breaking his hand in the contest, was competing in only his second fight at light heavyweight.
By the halfway stage, the underdog had stayed in contention, making life awkward for Buatsi, who operated with a solid defense to narrowly win the better stanzas.
The audience's tolerance diminished because of regular grabbing, with Parker falling to the floor several times during grappling.
Parker closed well, but several stanzas were difficult to score. Although, ex-champion Carl Frampton - working with the broadcast network - had it significantly in favor for Parker, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of power puncher David Benavidez, and Russian champion Dmitry Bivol ruling the division, the journey to titles - judging by this showing - still appears challenging.
Hatton Homage Motivates Local Rivalry Battle
In the secondary fight, Lyndon Arthur overcame Bradley Rea by split-decision in a excellent Manchester vs Manchester contest to secure the European light-heavyweight championship.
The venue grew hushed for a profoundly moving homage before the fight as ten bells sounded in remembrance of the city's native Hatton, who passed away 46 years old in September.
It was the initial significant broadcast match card in the location since Hatton's death. As the concluding sound disappeared, the silence gave way to a chant of "only one Hatton".
The competition inside the ropes matched the sentiment. The eventual winner was floored by a significant blow directly to the chin in the early round, rising shakily to his footing on the count of eight.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, the opponent - in competitive blue - was injured quickly, heavy swelling forming under his orbital area as the duo exchanged powerful shots.
The challenger, 27, connected with strong blows but the champion, thirty-four, responded in kind with effective uppercuts as the pace seldom decreased over the full distance.
Arthur narrowly won the decision with official scores of draw, close margin and clearer margin, but the two athletes were determined and full of heart, exactly what their inspiration Hatton embodied.
