British light-heavyweight Joshua Buatsi made a winning yet unimpressive beginning to his career under new promoters with a decision win over Parker in Manchester.
The Olympic bronze medallist's punch output seemingly secured him a majority decision in a tight 10-round contest at the Manchester venue.
But the challenger found success, connecting with powerful individual punches in a match where the styles failed to mesh, with constant grabbing disrupting the action.
The officials judged it 96-94 for to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest display but how do champions respond? They prevail," the victor stated in the ring as he was faced boos from the crowd.
The British fighter returned to winning ways after his first professional defeat - an epic battle with his previous opponent in last winter - to secure a 20th pro success.
Various analysts felt the challenger, thirty-one, merited the victory but the Derbyshire fighter suffered the second setback of his 28-fight career.
Buatsi Secures Victory in Uneventful Encounter
The fighter's advancement has stalled in recent years through management issues and extended periods of lack of fights.
Previously predicted as the rising talent of British boxing, he now is positioned trying to achieve expectations - maybe in what feels like a ultimate opportunity - under recent support.
He opened tentatively, with the two boxers willing to take risks in a calculated opening few rounds.
Parker, whose single earlier setback came at the lower weight class against his former opponent in two years ago after suffering a hand injury mid-fight, was making just his second appearance at light-heavyweight.
By the fight's midpoint, Parker had kept it close, causing problems for Buatsi, who utilized a tight guard to narrowly win the more effective rounds.
The spectators' acceptance diminished because of frequent holding, with the challenger slipping to the canvas various instances during grappling.
Parker closed well, but many rounds were hard to judge. Nevertheless, previous titleholder the boxing analyst - commentating on the broadcast network - had it strongly leaning for the challenger, scoring for Buatsi just one round.
Buatsi advances, but with the presence of power puncher Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Hatton Tribute Inspires All-Manchester Fight
In the secondary fight, Lyndon Arthur defeated Bradley Rea by divided decision in a terrific Manchester vs Manchester fight to capture the European light heavyweight belt.
The stadium became quiet for a deeply poignant tribute before the fight as 10 bells rang in memory of the city's native Hatton, who died aged 46 in September.
It was the first major televised match card in the location since Hatton's passing. As the concluding sound disappeared, the stillness became a chant of "there's only one Ricky Hatton".
The fighting during the bout reflected the sentiment. Arthur was knocked down by a powerful punch directly to the face in the initial stage, standing uncertainly to his footing on the eight count.
But the red-colored equipment of the fighter soon came forward again. From the other corner, Rea - in opposing blue - was marked up soon, heavy swelling developing under his orbital area as the pair landed punishing blows.
The challenger, twenty-seven, delivered effective strikes but Arthur, 34, responded in kind with stinging uppercuts as the pace rarely dropped over 12 rounds.
The victor narrowly won the decision with judges scorecards of 114-114, 115-113 and clearer margin, but the two athletes were relentless and full of heart, everything their idol Hatton represented.
