British light heavyweight Joshua Buatsi secured a victory yet unimpressive beginning to his career under fresh promotional backing with a points victory over Parker in Manchester.
The Olympic bronze medallist's work rate likely gained him a split decision in a close 10-round contest at the boxing arena.
But the challenger landed significant shots, landing some telling individual punches in a match where the approaches failed to mesh, with excessive holding spoiling the fight.
Two judges judged it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my greatest display but how do champions respond? They succeed," Buatsi said in the arena as he was met by disapproval from the crowd.
The British fighter got back to winning after his first professional defeat - an memorable fight with his previous opponent in February - to earn a twentieth professional win.
Several boxing experts felt Parker, 31, merited the decision but the Derbyshire fighter endured the second setback of his 28-fight career.
Buatsi Secures Victory in Slow Encounter
Buatsi's progress has stalled in recent times through management issues and long spells of lack of fights.
Once tipped as the rising talent of the British fight scene, he now finds himself trying to achieve expectations - perhaps in what feels like a final roll of the dice - under new promotional backing.
He began cautiously, with the two boxers prepared to take risks in a tentative early stages.
The challenger, whose only previous defeat came at super middleweight against John Ryder in two years ago after breaking his hand in the contest, was competing in only his second appearance at the higher weight class.
By the middle rounds, the underdog had made it competitive, creating difficulties for the favorite, who utilized a tight guard to barely take the cleaner stanzas.
The spectators' acceptance diminished amid frequent holding, with the challenger falling to the floor various instances during clinches.
The underdog closed well, but several stanzas were hard to judge. Although, ex-champion the boxing analyst - providing analysis for the broadcast network - had it significantly in favor for the challenger, awarding Buatsi just a single round.
Buatsi advances, but with the presence of hard hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the journey to titles - based on this performance - still appears challenging.
Ricky Hatton Memorial Inspires All-Manchester Battle
In the supporting bout, Lyndon Arthur defeated Bradley Rea by divided decision in a outstanding local rivalry contest to secure the European light heavyweight belt.
The venue became quiet for a extremely emotional tribute before the fight as 10 bells rang in honor of the city's native Ricky Hatton, who died at age 46 in recently.
It was the initial significant broadcast match card in the location since Hatton's death. As the concluding sound faded, the stillness transitioned to a roar of "there's only one Hatton".
The fighting inside the ropes matched the emotion. Arthur was floored by a significant blow squarely on the jaw in the second round, getting up unsteadily to his footing on the count of eight.
But the red-colored equipment of the fighter soon pressed ahead again. On the opposite side, Rea - in competitive blue - was damaged early, noticeable damage developing under his face as the duo landed hard punches.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with effective uppercuts as the intensity hardly diminished over the full distance.
The victor edged the result with official scores of draw, 115-113 and wider gap, but each competitor were relentless and full of heart, everything their idol Hatton represented.
