British light heavyweight Joshua Buatsi made a winning yet underwhelming start to life under new promoters with a unanimous decision over Parker in Manchester.
The Olympic medal winner's activity level likely gained him a majority decision in a close ten-round contest at the Co-op Live Arena.
But Parker landed significant shots, landing some telling clean blows in a match where the approaches didn't complement each other, with constant grabbing spoiling the action.
The scoring judges scored it 96-94 for to Buatsi, with the remaining official a 95-95.
"It wasn't my greatest display but what do champions do? They win," the victor stated in the arena as he was faced disapproval from the spectators.
The British fighter bounced back after his initial pro loss - an memorable fight with his previous opponent in last winter - to secure a 20th career victory.
Several boxing experts felt Parker, 31, deserved the decision but the British boxer endured the second setback of his 28-fight career.
Buatsi Earns Win in Slow Affair
His career development has slowed in the past few years through promotional disputes and considerable time of lack of fights.
Previously predicted as the next star of UK boxing, he now finds himself trying to fulfil that early promise - perhaps in what appears to be a final roll of the dice - under recent support.
He began cautiously, with neither fighter ready to take risks in a cagey early stages.
Parker, whose single earlier setback came at super middleweight against John Ryder in two years ago after breaking his hand in the contest, was making just his second fight at light-heavyweight.
By the halfway stage, Parker had kept it close, creating difficulties for the favorite, who utilized a protective stance to edge the cleaner rounds.
The crowd's patience decreased because of frequent holding, with Parker falling to the floor various instances during clinches.
Parker closed well, but multiple periods were challenging to assess. However, former world champion the boxing analyst - providing analysis for the broadcast network - had it particularly wide for Parker, awarding Buatsi just only one stanza.
The victor moves on, but with the presence of hard hitter Benavidez, and Eastern European fighter Dmitry Bivol leading the category, the path to championship success - on this evidence - still seems difficult.
Hatton Memorial Inspires Local Rivalry Contest
In the co-main event, Arthur defeated Bradley Rea by divided decision in a terrific Manchester vs Manchester contest to capture the European light heavyweight belt.
The venue grew hushed for a deeply poignant homage prior to the bout as a bell ceremony tolled in honor of Manchester's own Ricky Hatton, who succumbed 46 years old in September.
It was the premier televised boxing event in the location since Hatton's passing. As the last bell disappeared, the silence became a roar of "there's just one Hatton".
The competition inside the ropes reflected the sentiment. The eventual winner was floored by a powerful punch directly to the jaw in the early round, rising shakily to his position on the eight count.
But the red-colored equipment of Arthur soon came forward again. On the opposite side, the opponent - in opposing blue - was damaged early, noticeable damage forming under his orbital area as the duo traded powerful shots.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, responded in kind with effective uppercuts as the pace hardly diminished over twelve rounds.
The victor barely secured the decision with judges scorecards of even score, close margin and clearer margin, but each competitor were persistent and full of heart, all the qualities their idol Hatton represented.
