UK light-heavyweight Joshua Buatsi made a winning yet underwhelming start to life under fresh promotional backing with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a split decision in a close 10-round contest at the Co-op Live Arena.
But the challenger landed significant shots, delivering effective individual punches in a fight where the approaches didn't complement each other, with constant grabbing disrupting the contest.
Two judges scored it 96-94 for to the winner, with the third a 95-95.
"It wasn't my greatest performance but how do champions respond? They succeed," the victor said in the arena as he was met by disapproval from the crowd.
The British fighter got back to winning after his initial pro loss - an memorable fight with Callum Smith in last winter - to claim a 20th pro success.
Several boxing experts believed the challenger, thirty-one, deserved the decision but the British boxer endured the second loss of his 28-bout professional journey.
Buatsi Secures Triumph in Slow Encounter
Buatsi's progress has slowed in recent years through contract problems and extended periods of lack of fights.
Earlier forecast as the future of the British fight scene, he now finds himself trying to fulfil that early promise - maybe in what feels like a last chance - under fresh management.
He opened tentatively, with neither fighter willing to be aggressive in a tentative early stages.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after suffering a hand injury during the bout, was making just his second appearance at light-heavyweight.
By the halfway stage, the underdog had made it competitive, creating difficulties for the favorite, who worked behind a tight guard to narrowly win the better rounds.
The spectators' acceptance wore thin amid regular grabbing, with Parker going down several times during clinches.
The underdog ended stronger, but several stanzas were difficult to score. However, former world champion Carl Frampton - commentating on the broadcast network - had it significantly in favor for Parker, scoring for Buatsi just only one stanza.
Buatsi moves on, but with the caliber of hard hitter Benavidez, and Russian champion Dmitry Bivol leading the category, the road to world glory - judging by this showing - still seems difficult.
Hatton Homage Motivates Local Rivalry Battle
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a excellent local rivalry fight to capture the European light-heavyweight championship.
The stadium fell silent for a deeply poignant homage ahead of the contest as 10 bells rang in honor of the city's native Hatton, who passed away 46 years old in recently.
It was the premier televised boxing event in the location since Hatton's passing. As the concluding sound faded, the stillness transitioned to a chant of "there's just one Ricky Hatton".
The action within the ring matched the emotion. Arthur was knocked down by a significant blow squarely on the chin in the early round, standing uncertainly to his footing on the referee's count.
But the red-colored attire of the fighter soon pressed ahead again. Across the ring, the opponent - in rival City blue - was marked up quickly, noticeable damage developing under his orbital area as the duo exchanged punishing blows.
Rea, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with effective uppercuts as the action hardly diminished over twelve rounds.
The victor narrowly won the verdict with judges scorecards of even score, 115-113 and clearer margin, but each competitor were determined and full of heart, exactly what their inspiration Hatton embodied.
