UK light heavyweight Joshua Buatsi earned a win yet underwhelming beginning to life under new promoters with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a tight ten-round contest at the Co-op Live Arena.
But the challenger landed significant shots, connecting with powerful single shots in a match where the styles didn't complement each other, with excessive holding spoiling the contest.
The scoring judges judged it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my finest display but what defines champions? They succeed," Buatsi stated in the ringside as he was faced negative reactions from the spectators.
The Londoner returned to winning ways after his first professional defeat - an thrilling contest with his previous opponent in last winter - to claim a twentieth professional win.
Several boxing experts felt Parker, thirty-one, merited the victory but the contender suffered the second setback of his 28-match career.
Buatsi Secures Win in Uneventful Encounter
The fighter's advancement has plateaued in the past few years through promotional disputes and considerable time of inactivity.
Previously predicted as the future of UK boxing, he now finds himself trying to realize his potential - perhaps in what seems like a last chance - under fresh management.
He opened tentatively, with the two boxers ready to be aggressive in a cagey early stages.
The challenger, whose single earlier setback came at super middleweight against his former opponent in two years ago after damaging his hand mid-fight, was participating in his second fight at the higher weight class.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who operated with a solid defense to barely take the more effective stanzas.
The crowd's patience decreased because of regular grabbing, with Parker slipping to the canvas multiple occasions during close exchanges.
Parker finished the stronger, but multiple periods were challenging to assess. Although, former world champion Carl Frampton - providing analysis for Dazn - had it strongly leaning for Parker, giving Buatsi just only one stanza.
The victor progresses, but with the likes of heavy hitter Benavidez, and Eastern European fighter Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still seems difficult.
Ricky Hatton Tribute Fuels Local Rivalry Contest
In the supporting bout, Arthur beat Rea by split-decision in a excellent local rivalry fight to win the European light-heavyweight belt.
The arena became quiet for a extremely emotional homage prior to the bout as 10 bells sounded in remembrance of the city's native Ricky Hatton, who passed away aged 46 in last month.
It was the initial significant broadcast boxing event in the urban center since the passing of Hatton. As the last bell faded, the quiet became a roar of "only one Ricky Hatton".
The fighting inside the ropes equaled the feeling. Arthur was floored by a significant blow directly to the chin in the second round, standing uncertainly to his feet on the eight count.
But the traditional red equipment of the fighter soon pressed ahead again. Across the ring, Rea - in rival City blue - was injured quickly, significant bruising forming under his orbital area as the duo traded hard punches.
The challenger, 27, landed power punches but Arthur, 34, responded in kind with stinging uppercuts as the pace rarely dropped over 12 rounds.
Arthur edged the verdict with judges scorecards of draw, close margin and wider gap, but the two athletes were determined and brave, all the qualities their inspiration Hatton stood for.
