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 bronze medallist's punch output likely gained him a judges' verdict in a tight ten-round bout at the Co-op Live Arena.
But the challenger had his moments, delivering effective individual punches in a contest where the techniques never quite clicked, with excessive holding disrupting the contest.
The officials judged it 96-94 in favor to the winner, with the final judge a 95-95 draw.
"It wasn't my best display but what do champions do? They prevail," the victor commented in the ring as he was met by disapproval from the audience.
The Londoner got back to winning after his initial pro loss - an memorable fight with his previous opponent in last winter - to claim a 20th pro success.
Several boxing experts thought Parker, 31, should have been awarded the win but the contender suffered the second defeat of his 28-match career.
The Champion Secures Win in Slow Encounter
His career development has plateaued in the past few years through management issues and considerable time of inactivity.
Once tipped as the rising talent of British boxing, he now stands trying to fulfil that early promise - perhaps in what feels like a last chance - under new promotional backing.
He opened tentatively, with the two boxers prepared to take risks in a cagey initial rounds.
Parker, whose single earlier setback came at super middleweight against his former opponent in two years ago after damaging his hand during the bout, was making just his second appearance at light heavyweight.
By the fight's midpoint, the underdog had stayed in contention, making life awkward for the favorite, who utilized a protective stance to narrowly win the better periods.
The audience's tolerance wore thin amid regular grabbing, with Parker going down several times during clinches.
Parker finished the stronger, but multiple periods were hard to judge. Although, former world champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, giving Buatsi just a single round.
Buatsi advances, but with the caliber of heavy hitter David Benavidez, and Russian champion Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still seems difficult.
Hatton Tribute Motivates All-Manchester Fight
In the supporting bout, Arthur overcame Bradley Rea by close verdict in a excellent all-Manchester battle to secure the European light heavyweight title.
The venue fell silent for a profoundly moving tribute ahead of the contest as 10 bells sounded in honor of the city's native Hatton, who died at age 46 in recently.
It was the premier televised boxing event in the urban center since the passing of Hatton. As the final chime disappeared, the quiet became a roar of "only one Ricky Hatton".
The competition during the bout equaled the emotion. The eventual winner was floored by a powerful punch flush on the chin in the second round, standing uncertainly to his feet on the referee's count.
But the red-colored attire of the fighter soon advanced again. On the opposite side, the opponent - in rival City blue - was injured soon, significant bruising developing under his eye as the fighters exchanged punishing blows.
The challenger, 27, delivered effective strikes but the champion, thirty-four, fought fire with fire with powerful upward punches as the action rarely dropped over twelve rounds.
The victor narrowly won the decision with scoring tallies of 114-114, narrow lead and wider gap, but both fighters were determined and full of heart, exactly what their idol Hatton embodied.
