UK light-heavyweight Joshua Buatsi secured a victory yet underwhelming debut to his career under new promoters with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a competitive 10-round contest at the boxing arena.
But Parker had his moments, connecting with powerful single shots in a match where the approaches didn't complement each other, with constant grabbing marring the contest.
The officials scored it 96-94 to Buatsi, with the final judge a even score.
"It wasn't my greatest showing but what defines champions? They win," the victor said in the arena as he was faced negative reactions from the spectators.
The British fighter bounced back after his first professional defeat - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Several boxing experts believed the challenger, thirty-one, should have been awarded the victory but the Derbyshire fighter suffered the second defeat of his 28-bout professional journey.
Buatsi Secures Victory in Uneventful Match
Buatsi's progress has stalled in recent years through management issues and considerable time of inactivity.
Previously predicted as the next star of the British fight scene, he now is positioned trying to realize his potential - possibly in what appears to be a final roll of the dice - under recent support.
He began cautiously, with neither fighter willing to be aggressive in a tentative opening few rounds.
The challenger, whose only previous defeat came at super-middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was competing in only his second bout at light heavyweight.
By the middle rounds, Parker had stayed in contention, causing problems for Buatsi, who operated with a protective stance to narrowly win the better rounds.
The crowd's patience diminished because of constant clinching, with Parker going down multiple occasions during clinches.
Parker finished the stronger, but several stanzas were difficult to score. Nevertheless, former world champion Carl Frampton - working with the broadcast network - had it particularly wide for the challenger, scoring for Buatsi just only one stanza.
Buatsi progresses, but with the presence of hard hitter David Benavidez, and Russian star Bivol dominating the weight class, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Homage Fuels Local Rivalry Battle
In the supporting bout, Lyndon Arthur defeated Bradley Rea by close verdict in a excellent local rivalry fight to secure the continental championship.
The arena became quiet for a extremely emotional tribute prior to the bout as a bell ceremony sounded in remembrance of Manchester's own Ricky Hatton, who passed away 46 years old in recently.
It was the premier televised fight night in the city since Hatton's death. As the last bell faded, the quiet became a shout of "only one Hatton".
The competition within the ring equaled the emotion. Arthur was sent to the canvas by a left hook directly to the face in the initial stage, rising shakily to his position on the count of eight.
But the red-colored attire of the fighter soon advanced again. From the other corner, the opponent - in opposing blue - was damaged soon, noticeable damage developing under his orbital area as the pair landed punishing blows.
Rea, twenty-seven, delivered effective strikes but the champion, thirty-four, fought fire with fire with stinging uppercuts as the pace seldom decreased over the full distance.
The victor narrowly won the decision with scoring tallies of draw, close margin and 115-112, but each competitor were persistent and courageous, everything their inspiration Hatton embodied.
