British light-heavyweight Joshua Buatsi secured a victory yet unimpressive beginning to life under new promoters with a decision win over Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a split decision in a close 10-round fight at the boxing arena.
But the challenger had his moments, landing some telling clean blows in a fight where the approaches didn't complement each other, with constant grabbing marring the fight.
The officials scored it 96-94 in favor to the winner, with the third a 95-95 draw.
"It wasn't my finest performance but what do champions do? They prevail," the victor stated in the ringside as he was greeted with disapproval from the crowd.
The British fighter bounced back after his initial pro loss - an memorable fight with Callum Smith in last winter - to secure a twentieth professional win.
Various analysts thought the challenger, 31, deserved the win but the Derbyshire fighter endured the second setback of his 28-bout career.
Buatsi Claims Victory in Uneventful Affair
His career development has slowed in the past few years through promotional disputes and long spells of inactivity.
Once tipped as the rising talent of UK boxing, he now stands trying to realize his potential - possibly in what feels like a last chance - under fresh management.
He started carefully, with both competitors prepared to take risks in a cagey early stages.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in two years ago after suffering a hand injury in the contest, was making just his second fight at light heavyweight.
By the fight's midpoint, the underdog had kept it close, making life awkward for the favorite, who utilized a solid defense to barely take the cleaner periods.
The crowd's patience diminished amid frequent holding, with the challenger slipping to the canvas multiple occasions during close exchanges.
Parker finished the stronger, but several stanzas were hard to judge. Nevertheless, ex-champion the boxing analyst - commentating on Dazn - had it significantly in favor for the challenger, awarding Buatsi just a single round.
The victor advances, but with the caliber of power puncher Benavidez, and Russian star Dmitry Bivol ruling the division, the path to championship success - based on this performance - still appears challenging.
Hatton Homage Fuels All-Manchester Battle
In the supporting bout, Lyndon Arthur beat Bradley Rea by split-decision in a terrific local rivalry battle to secure the continental belt.
The stadium grew hushed for a profoundly moving homage before the fight as a bell ceremony tolled in memory of local hero Ricky Hatton, who passed away at age 46 in September.
It was the initial significant broadcast match card in the urban center since Hatton's death. As the final chime faded, the stillness transitioned to a roar of "there's just one Hatton".
The fighting within the ring equaled the sentiment. The eventual winner was floored by a powerful punch directly to the chin in the early round, rising shakily to his position on the count of eight.
But the traditional red equipment of the fighter soon came forward again. On the opposite side, Rea - in competitive blue - was marked up quickly, significant bruising developing under his orbital area as the duo landed punishing blows.
Rea, twenty-seven, landed power punches but Arthur, 34, matched the intensity with stinging uppercuts as the intensity seldom decreased over twelve rounds.
Arthur edged the decision with scoring tallies of 114-114, narrow lead and 115-112, but each competitor were persistent and brave, all the qualities their idol the legend represented.
