British light-heavyweight Joshua Buatsi secured a victory yet unimpressive debut to his career under recent management with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a split decision in a close 10-round bout at the Co-op Live Arena.
But Parker had his moments, landing some telling single shots in a contest where the styles didn't complement each other, with frequent clinching disrupting the fight.
The officials scored it 96-94 for to Buatsi, with the third a 95-95 draw.
"It wasn't my best performance but how do champions respond? They succeed," Buatsi stated in the ring as he was faced boos from the spectators.
The British fighter returned to winning ways after his maiden career setback - an epic battle with his previous opponent in February - to secure a 20th pro success.
Several boxing experts thought the challenger, thirty-one, should have been awarded the win but the contender suffered the second setback of his 28-match career.
The Champion Secures Win in Slow Encounter
The fighter's advancement has plateaued in the past few years through management issues and long spells of inactivity.
Earlier forecast as the next star of the British fight scene, he now stands trying to fulfil that early promise - maybe in what seems like a last chance - under recent support.
He began cautiously, with neither fighter willing to take risks in a cagey opening few rounds.
The challenger, whose sole prior loss came at super middleweight against John Ryder in two years ago after damaging his hand in the contest, was participating in his second bout at light heavyweight.
By the fight's midpoint, the underdog had made it competitive, making life awkward for Buatsi, who utilized a protective stance to edge the more effective stanzas.
The crowd's patience decreased during regular grabbing, with the challenger falling to the floor several times during close exchanges.
The underdog finished the stronger, but several stanzas were difficult to score. However, former world champion the boxing analyst - commentating on Dazn - had it significantly in favor for Parker, giving Buatsi just one round.
The victor advances, but with the presence of power puncher Benavidez, and Russian champion Dmitry Bivol leading the category, the road to world glory - judging by this showing - still seems difficult.
Hatton Tribute Fuels Local Rivalry Contest
In the secondary fight, Lyndon Arthur overcame Rea by split-decision in a excellent local rivalry fight to win the continental belt.
The stadium grew hushed for a deeply poignant memorial prior to the bout as 10 bells rang in remembrance of local hero Hatton, who passed away at age 46 in recently.
It was the initial significant broadcast fight night in the city since the passing of Hatton. As the final chime disappeared, the silence became a roar of "there's just one Ricky Hatton".
The action within the ring matched the feeling. Arthur was sent to the canvas by a left hook flush on the chin in the early round, getting up unsteadily to his feet on the count of eight.
But the traditional red shorts of the fighter soon pressed ahead again. From the other corner, Rea - in competitive blue - was injured early, heavy swelling developing under his face as the pair exchanged powerful shots.
Rea, 27, connected with strong blows but Arthur, 34, fought fire with fire with effective uppercuts as the action hardly diminished over 12 rounds.
Arthur edged the result with scoring tallies of draw, 115-113 and 115-112, but the two athletes were determined and brave, all the qualities their idol the legend embodied.
