UK light heavyweight Joshua Buatsi made a winning yet underwhelming debut to his career under recent management with a unanimous decision over Parker in the Manchester arena.
The Olympic bronze medallist's punch output appeared to earn him a split decision in a close 10-round fight at the boxing arena.
But the challenger had his moments, landing some telling clean blows in a match where the techniques didn't complement each other, with constant grabbing spoiling the fight.
The officials had it 96-94 in favor to the winner, with the remaining official a even score.
"It wasn't my finest performance but what defines champions? They win," Buatsi said in the ringside as he was met by negative reactions from the crowd.
The Londoner returned to winning ways after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a 20th career victory.
Various analysts felt the challenger, 31, should have been awarded the decision but the contender endured the second setback of his 28-bout professional journey.
Buatsi Earns Triumph in Uneventful Match
The fighter's advancement has stalled in recent years through contract problems and considerable time of inactivity.
Once tipped as the future of British boxing, he now stands trying to realize his potential - possibly in what seems like a final roll of the dice - under new promotional backing.
He started carefully, with both competitors prepared to take risks in a cagey early stages.
The challenger, whose single earlier setback came at super-middleweight against John Ryder in two years ago after breaking his hand in the contest, was participating in his second bout at light-heavyweight.
By the halfway stage, Parker had stayed in contention, creating difficulties for Buatsi, who worked behind a tight guard to edge the cleaner stanzas.
The audience's tolerance diminished during constant clinching, with Parker slipping to the canvas multiple occasions during clinches.
The underdog finished the stronger, but several stanzas were hard to judge. However, ex-champion the boxing analyst - commentating on the broadcast network - had it significantly in favor for Parker, awarding Buatsi just only one stanza.
The victor moves on, but with the caliber of hard hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - based on this performance - still appears challenging.
Hatton Homage Motivates Local Rivalry Fight
In the secondary fight, Lyndon Arthur overcame Bradley Rea by split-decision in a excellent Manchester vs Manchester fight to capture the continental belt.
The arena fell silent for a profoundly moving memorial ahead of the contest as ten bells sounded in honor of local hero Hatton, who passed away 46 years old in last month.
It was the initial significant broadcast fight night in the urban center since the passing of Hatton. As the concluding sound ended, the quiet became a roar of "only one Hatton".
The fighting during the bout matched the sentiment. Arthur was knocked down by a powerful punch squarely on the jaw in the early round, getting up unsteadily to his footing on the count of eight.
But the red-colored attire of the fighter soon advanced again. On the opposite side, the opponent - in rival City blue - was marked up quickly, noticeable damage developing under his orbital area as the fighters exchanged punishing blows.
Rea, 27, landed power punches but Arthur, thirty-four, matched the intensity with effective uppercuts as the action hardly diminished over twelve rounds.
Arthur edged the result with official scores of 114-114, 115-113 and clearer margin, but the two athletes were persistent and courageous, all the qualities their hero Hatton represented.
