British light heavyweight Joshua Buatsi made a winning yet unimpressive debut to his career under fresh promotional backing with a points victory over Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a split decision in a tight ten-round contest at the boxing arena.
But the challenger found success, delivering effective individual punches in a contest where the techniques never quite clicked, with constant grabbing marring the action.
Two judges had it 96-94 in favor to Buatsi, with the final judge a even score.
"It wasn't my greatest showing but what do champions do? They succeed," the victor said in the ring as he was faced disapproval from the crowd.
The Londoner returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to claim a 20th pro success.
Various analysts believed the challenger, 31, merited the win but the British boxer experienced the second defeat of his 28-bout career.
The Champion Secures Victory in Uneventful Match
The fighter's advancement has plateaued in recent years through contract problems and long spells of inactivity.
Once tipped as the rising talent of British boxing, he now finds himself trying to realize his potential - maybe in what seems like a ultimate opportunity - under fresh management.
He started carefully, with both competitors prepared to be aggressive in a tentative opening few rounds.
Parker, whose single earlier setback came at super-middleweight against his former opponent in two years ago after suffering a hand injury mid-fight, was making just his second bout at the higher weight class.
By the middle rounds, the underdog had kept it close, making life awkward for Buatsi, who utilized a solid defense to barely take the more effective rounds.
The audience's tolerance decreased amid regular grabbing, with the challenger falling to the floor several times during clinches.
The underdog closed well, but multiple periods were difficult to score. Nevertheless, former world champion the boxing analyst - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just one round.
Buatsi moves on, but with the caliber of heavy hitter Benavidez, and Russian star Dmitry Bivol leading the category, the path to championship success - judging by this showing - still seems difficult.
Ricky Hatton Memorial Fuels Manchester Derby Contest
In the secondary fight, Lyndon Arthur beat Bradley Rea by split-decision in a terrific all-Manchester fight to win the European light-heavyweight title.
The stadium became quiet for a extremely emotional homage prior to the bout as a bell ceremony rang in honor of Manchester's own Ricky Hatton, who died 46 years old in recently.
It was the premier televised fight night in the city since Hatton's passing. As the concluding sound ended, the stillness gave way to a shout of "there's just one Hatton".
The action inside the ropes matched the emotion. Arthur was sent to the canvas by a left hook squarely on the jaw in the early round, getting up unsteadily to his feet on the count of eight.
But the traditional red shorts of Arthur soon came forward again. From the other corner, the opponent - in rival City blue - was marked up early, significant bruising developing under his eye as the duo traded hard punches.
The challenger, twenty-seven, landed power punches but the champion, 34, matched the intensity with effective uppercuts as the pace hardly diminished over the full distance.
Arthur edged the verdict with judges scorecards of 114-114, narrow lead and clearer margin, but each competitor were determined and full of heart, all the qualities their inspiration Hatton embodied.
