British light-heavyweight Joshua Buatsi secured a victory yet underwhelming beginning to his career under recent management with a unanimous decision over Parker in Manchester.
The Olympic bronze medallist's activity level seemingly secured him a majority decision in a close ten-round fight at the Manchester venue.
But Parker had his moments, delivering effective single shots in a fight where the techniques didn't complement each other, with constant grabbing spoiling the fight.
The scoring judges scored it 96-94 in favor to the winner, with the final judge a 95-95.
"It wasn't my finest showing but how do champions respond? They prevail," the victor commented in the arena as he was met by disapproval from the spectators.
The Londoner bounced back after his initial pro loss - an thrilling contest with his previous opponent in last winter - to earn a twentieth professional win.
Various analysts thought the challenger, thirty-one, deserved the decision but the Derbyshire fighter experienced the second loss of his 28-fight professional journey.
The Champion Earns Triumph in Slow Affair
The fighter's advancement has stalled in the past few years through contract problems and considerable time of inactivity.
Once tipped as the rising talent of the British fight scene, he now is positioned trying to realize his potential - perhaps in what feels like a ultimate opportunity - under recent support.
He began cautiously, with both competitors willing to take risks in a tentative early stages.
The challenger, whose only previous defeat came at super middleweight against his former opponent in two years ago after damaging his hand during the bout, was competing in only his second fight at light heavyweight.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who utilized a solid defense to narrowly win the better periods.
The spectators' acceptance wore thin during constant clinching, with the challenger slipping to the canvas multiple occasions during grappling.
Parker closed well, but multiple periods were hard to judge. However, ex-champion the boxing analyst - working with Dazn - had it strongly leaning for the challenger, giving Buatsi just one round.
The victor moves on, but with the caliber of power puncher Benavidez, and Russian star Bivol leading the category, the road to world glory - based on this performance - still seems difficult.
Hatton Tribute Fuels Manchester Derby Fight
In the co-main event, Lyndon Arthur defeated Bradley Rea by divided decision in a excellent local rivalry fight to capture the European light-heavyweight title.
The stadium grew hushed for a extremely emotional tribute before the fight as a bell ceremony sounded in remembrance of local hero Ricky Hatton, who died at age 46 in last month.
It was the initial significant broadcast match card in the city since the passing of Hatton. As the concluding sound disappeared, the stillness gave way to a chant of "there's just one Hatton".
The competition within the ring matched the emotion. Arthur was floored by a significant blow directly to the chin in the early round, standing uncertainly to his feet on the eight count.
But the red-colored attire of Arthur soon pressed ahead again. From the other corner, the opponent - in opposing blue - was marked up quickly, noticeable damage forming under his face as the pair traded hard punches.
The challenger, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with stinging uppercuts as the pace hardly diminished over twelve rounds.
Arthur edged the decision with judges scorecards of even score, narrow lead and clearer margin, but the two athletes were relentless and full of heart, everything their idol the legend embodied.
