UK light heavyweight Joshua Buatsi secured a victory yet unimpressive debut to his career under new promoters with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's work rate seemingly secured him a judges' verdict in a tight 10-round fight at the boxing arena.
But Parker found success, landing some telling individual punches in a contest where the approaches failed to mesh, with frequent clinching spoiling the action.
The officials scored it 96-94 for to the winner, with the final judge a 95-95.
"It wasn't my best showing but what defines champions? They win," the victor stated in the ringside as he was faced disapproval from the audience.
The British fighter bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to earn a 20th career victory.
Some ringside observers thought the challenger, 31, deserved the decision but the contender experienced the second setback of his 28-fight professional journey.
Buatsi Earns Triumph in Uneventful Affair
The fighter's advancement has stalled in recent years through management issues and considerable time of inactivity.
Previously predicted as the next star of British boxing, he now stands trying to fulfil that early promise - possibly in what seems like a last chance - under new promotional backing.
He started carefully, with the two boxers ready to take risks 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 suffering a hand injury in the contest, was participating in his second bout at light-heavyweight.
By the middle rounds, the underdog had kept it close, creating difficulties for the favorite, who utilized a protective stance to barely take the cleaner stanzas.
The crowd's patience decreased because of constant clinching, with Parker falling to the floor various instances during close exchanges.
The underdog ended stronger, but multiple periods were challenging to assess. Nevertheless, former world champion Carl Frampton - commentating on the broadcast network - had it strongly leaning for Parker, giving Buatsi just only one stanza.
Buatsi advances, but with the presence of heavy hitter Benavidez, and Russian champion Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still appears challenging.
Hatton Tribute Fuels All-Manchester Fight
In the supporting bout, Arthur defeated Rea by close verdict in a excellent local rivalry contest to win the European light-heavyweight championship.
The arena grew hushed for a deeply poignant memorial before the fight as 10 bells tolled in memory of local hero Hatton, who passed away at age 46 in September.
It was the first major televised match card in the city since Hatton's death. As the concluding sound faded, the stillness became a chant of "only one Hatton".
The competition during the bout reflected the emotion. Arthur was sent to the canvas by a left hook flush on the face in the early round, standing uncertainly to his footing on the referee's count.
But the Manchester United-red equipment of Arthur soon pressed ahead again. From the other corner, the opponent - in competitive blue - was marked up early, heavy swelling appearing under his eye as the fighters exchanged powerful shots.
The challenger, twenty-seven, connected with strong blows but Arthur, 34, responded in kind with powerful upward punches as the intensity rarely dropped over the full distance.
The victor narrowly won the result with judges scorecards of 114-114, narrow lead and wider gap, but each competitor were relentless and brave, all the qualities their inspiration Hatton represented.
