UK light heavyweight Joshua Buatsi made a winning yet unimpressive debut to his career under fresh promotional backing with a decision win over Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a split decision in a tight ten-round contest at the boxing arena.
But Parker landed significant shots, connecting with powerful clean blows in a contest where the styles never quite clicked, with excessive holding spoiling the contest.
Two judges had it 96-94 to Buatsi, with the final judge a 95-95.
"It wasn't my greatest performance but what do champions do? They prevail," Buatsi said in the ring as he was met by negative reactions from the spectators.
The British fighter returned to winning ways after his initial pro loss - an memorable fight with Callum Smith in February - to claim a 20th career victory.
Some ringside observers believed the challenger, thirty-one, should have been awarded the win but the Derbyshire fighter endured the second loss of his 28-fight career.
The Champion Claims Triumph in Uneventful Match
Buatsi's progress has slowed in the past few years through management issues and extended periods of lack of fights.
Earlier forecast as the next star of UK boxing, he now finds himself trying to realize his potential - possibly in what seems like a final roll of the dice - under recent support.
He began cautiously, with both competitors willing to be aggressive in a cagey early stages.
Parker, whose sole prior loss came at the lower weight class against his former opponent in two years ago after breaking his hand in the contest, was competing in only his second appearance at light-heavyweight.
By the fight's midpoint, Parker had stayed in contention, causing problems for the favorite, who utilized a tight guard to edge the more effective stanzas.
The spectators' acceptance decreased because of frequent holding, with Parker falling to the floor multiple occasions during clinches.
Parker ended stronger, but several stanzas were difficult to score. However, ex-champion the boxing analyst - working with the broadcast network - had it significantly in favor for Parker, giving Buatsi just one round.
The victor advances, but with the caliber of power puncher Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - based on this performance - still looks steep.
Ricky Hatton Memorial Inspires Manchester Derby Contest
In the secondary fight, Lyndon Arthur overcame Rea by divided decision in a outstanding all-Manchester battle to capture the European light-heavyweight belt.
The stadium fell silent for a extremely emotional memorial ahead of the contest as ten bells rang in memory of local hero Ricky Hatton, who died at age 46 in September.
It was the first major televised match card in the urban center since the passing of Hatton. As the concluding sound disappeared, the quiet became a shout of "there's only one Ricky Hatton".
The action inside the ropes matched the sentiment. The eventual winner was sent to the canvas by a significant blow flush on the face in the initial stage, getting up unsteadily to his position on the count of eight.
But the red-colored attire of the fighter soon came forward again. Across the ring, the opponent - in opposing blue - was damaged soon, significant bruising forming under his orbital area as the pair exchanged punishing blows.
The challenger, 27, delivered effective strikes but the champion, 34, responded in kind with powerful upward punches as the pace seldom decreased over the full distance.
Arthur barely secured the result with scoring tallies of even score, 115-113 and wider gap, but the two athletes were determined and courageous, everything their hero Hatton embodied.
