British light-heavyweight Joshua Buatsi made a winning yet disappointing beginning to life under new promoters with a decision win over Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a tight ten-round bout at the Co-op Live Arena.
But the challenger had his moments, connecting with powerful individual punches in a match where the approaches didn't complement each other, with excessive holding marring the fight.
The officials had it 96-94 to the winner, with the remaining official a even score.
"It wasn't my greatest showing but how do champions respond? They win," Buatsi commented in the arena as he was greeted with negative reactions from the crowd.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to earn a twentieth professional win.
Some ringside observers thought Parker, thirty-one, merited the decision but the British boxer suffered the second loss of his 28-match professional journey.
Buatsi Claims Win in Slow Match
The fighter's advancement has plateaued in the past few years through contract problems and extended periods of inactivity.
Previously predicted as the rising talent of the British fight scene, he now stands trying to realize his potential - possibly in what feels like a final roll of the dice - under new promotional backing.
He opened tentatively, with the two boxers willing to be aggressive in a cagey opening few rounds.
The challenger, whose only previous defeat came at super middleweight against John Ryder in two years ago after suffering a hand injury mid-fight, was participating in his second bout at the higher weight class.
By the halfway stage, Parker had stayed in contention, causing problems for Buatsi, who operated with a tight guard to narrowly win the better periods.
The spectators' acceptance decreased because of frequent holding, with the challenger going down multiple occasions during clinches.
Parker finished the stronger, but many rounds were difficult to score. However, previous titleholder the boxing analyst - commentating on the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just one round.
The victor progresses, but with the presence of hard hitter Benavidez, and Eastern European fighter Bivol leading the category, the road to world glory - on this evidence - still seems difficult.
Ricky Hatton Homage Motivates All-Manchester Contest
In the supporting bout, Lyndon Arthur defeated Bradley Rea by split-decision in a excellent all-Manchester fight to secure the European light-heavyweight championship.
The arena became quiet for a profoundly moving homage prior to the bout as 10 bells rang in honor of local hero Ricky Hatton, who died aged 46 in recently.
It was the premier televised boxing event in the urban center since Hatton's death. As the final chime faded, the silence became a shout of "there's just one Ricky Hatton".
The competition during the bout equaled the emotion. Arthur was knocked down by a significant blow squarely on the face in the early round, getting up unsteadily to his feet on the count of eight.
But the Manchester United-red shorts of Arthur soon pressed ahead again. Across the ring, Rea - in rival City blue - was marked up early, significant bruising developing under his face as the fighters landed punishing blows.
The challenger, twenty-seven, connected with strong blows but the champion, 34, fought fire with fire with powerful upward punches as the pace rarely dropped over 12 rounds.
Arthur barely secured the result with scoring tallies of even score, 115-113 and clearer margin, but each competitor were relentless and brave, everything their hero Hatton stood for.
