UK light-heavyweight Joshua Buatsi made a winning yet underwhelming start to life under recent management with a unanimous decision over Parker in the Manchester arena.
The Olympic medal winner's punch output seemingly secured him a judges' verdict in a tight ten-round fight at the Co-op Live Arena.
But the challenger found success, connecting with powerful individual punches in a contest where the techniques never quite clicked, with excessive holding spoiling the fight.
The scoring judges scored it 96-94 for to Buatsi, with the third a 95-95.
"It wasn't my greatest performance but what defines champions? They win," Buatsi commented in the ring as he was greeted with boos from the audience.
The British fighter got back to winning after his initial pro loss - an epic battle with Callum Smith in February - to secure a 20th career victory.
Several boxing experts felt the challenger, thirty-one, should have been awarded the decision but the contender suffered the second defeat of his 28-match career.
Buatsi Secures Triumph in Dull Affair
Buatsi's progress has stalled in the past few years through promotional disputes and considerable time of lack of fights.
Earlier forecast as the future of the British fight scene, he now stands trying to realize his potential - maybe in what seems like a final roll of the dice - under new promotional backing.
He opened tentatively, with the two boxers willing to be aggressive in a calculated initial rounds.
Parker, whose single earlier setback came at the lower weight class against John Ryder in two years ago after breaking his hand mid-fight, was making just his second appearance at light heavyweight.
By the middle rounds, Parker had kept it close, causing problems for Buatsi, who utilized a solid defense to edge the more effective rounds.
The audience's tolerance decreased amid regular grabbing, with the challenger going down various instances during grappling.
The underdog closed well, but several stanzas were hard to judge. However, former world champion Carl Frampton - providing analysis for Dazn - had it significantly in favor for Parker, giving Buatsi just a single round.
The victor advances, but with the caliber of power puncher Benavidez, and Russian star Dmitry Bivol dominating the weight class, the road to world glory - based on this performance - still seems difficult.
Hatton Tribute Inspires Local Rivalry Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by close verdict in a excellent Manchester vs Manchester contest to capture the continental title.
The arena fell silent for a profoundly moving tribute prior to the bout as 10 bells tolled in remembrance of Manchester's own Hatton, who succumbed 46 years old in recently.
It was the first major televised fight night in the urban center since the passing of Hatton. As the final chime ended, the silence became a chant of "only one Hatton".
The competition within the ring equaled the sentiment. Arthur was knocked down by a significant blow flush on the face in the initial stage, standing uncertainly to his position on the eight count.
But the Manchester United-red attire of the fighter soon advanced again. Across the ring, the opponent - in competitive blue - was marked up early, heavy swelling forming under his eye as the pair landed powerful shots.
The challenger, 27, landed power punches but the champion, 34, fought fire with fire with effective uppercuts as the intensity seldom decreased over twelve rounds.
Arthur narrowly won the decision with judges scorecards of even score, close margin and clearer margin, but the two athletes were persistent and full of heart, everything their inspiration Hatton embodied.
