British light-heavyweight Joshua Buatsi made a winning yet underwhelming beginning to life under fresh promotional backing with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's work rate appeared to earn him a judges' verdict in a competitive ten-round fight at the Co-op Live Arena.
But the challenger had his moments, delivering effective single shots in a match where the styles never quite clicked, with frequent clinching spoiling the contest.
The officials had it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my finest showing but how do champions respond? They prevail," Buatsi commented in the ringside as he was greeted with disapproval from the spectators.
The Londoner returned to winning ways after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a twentieth professional win.
Various analysts believed Parker, 31, merited the victory but the British boxer suffered the second defeat of his 28-fight professional journey.
Buatsi Secures Triumph in Dull Encounter
His career development has plateaued in recent times through promotional disputes and long spells of lack of fights.
Previously predicted as the future of UK boxing, he now is positioned trying to fulfil that early promise - perhaps in what feels like a last chance - under new promotional backing.
He opened tentatively, with both competitors willing to overcommit in a tentative opening few rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after suffering a hand injury in the contest, was competing in only his second bout at light-heavyweight.
By the middle rounds, Parker had stayed in contention, making life awkward for Buatsi, who utilized a protective stance to barely take the cleaner rounds.
The crowd's patience decreased because of regular grabbing, with Parker falling to the floor various instances during close exchanges.
Parker closed well, but many rounds were challenging to assess. Nevertheless, former world champion Carl Frampton - providing analysis for the broadcast network - had it particularly wide for Parker, awarding Buatsi just only one stanza.
The victor advances, but with the presence of hard hitter Benavidez, and Russian star Bivol leading the category, the journey to titles - judging by this showing - still looks steep.
Hatton Homage Inspires All-Manchester Fight
In the co-main event, Arthur beat Rea by close verdict in a excellent all-Manchester battle to win the continental championship.
The venue grew hushed for a deeply poignant homage ahead of the contest as ten bells tolled in memory of the city's native Ricky Hatton, who passed away 46 years old in recently.
It was the initial significant broadcast fight night in the city since the passing of Hatton. As the concluding sound disappeared, the quiet gave way to a chant of "there's just one Hatton".
The action inside the ropes matched the feeling. The eventual winner was floored by a powerful punch squarely on the jaw in the early round, rising shakily to his feet on the count of eight.
But the traditional red attire of Arthur soon came forward again. Across the ring, the opponent - in competitive blue - was marked up early, noticeable damage appearing under his eye as the fighters landed hard punches.
The challenger, 27, connected with strong blows but Arthur, 34, responded in kind with powerful upward punches as the action seldom decreased over twelve rounds.
The victor barely secured the result with scoring tallies of 114-114, narrow lead and clearer margin, but the two athletes were persistent and full of heart, exactly what their inspiration Hatton stood for.
