British light-heavyweight Joshua Buatsi made a winning yet disappointing debut to his career under new promoters with a decision win over Parker in the Manchester arena.
The Olympic medal winner's activity level appeared to earn him a majority decision in a close 10-round bout at the Manchester venue.
But the challenger found success, delivering effective individual punches in a contest where the styles never quite clicked, with frequent clinching marring the fight.
The officials had it 96-94 in favor to the winner, with the third a even score.
"It wasn't my best showing but how do champions respond? They succeed," Buatsi stated in the ring as he was greeted with disapproval from the spectators.
The Londoner bounced back after his maiden career setback - an thrilling contest with Callum Smith in February - to earn a twentieth professional win.
Several boxing experts believed the challenger, 31, merited the win but the British boxer experienced the second setback of his 28-match professional journey.
Buatsi Earns Victory in Slow Encounter
His career development has plateaued in recent times through contract problems and long spells of inactivity.
Previously predicted as the rising talent of UK boxing, he now finds himself trying to realize his potential - perhaps in what feels like a last chance - under fresh management.
He started carefully, with both competitors ready to overcommit in a calculated early stages.
Parker, whose only previous defeat came at super-middleweight against John Ryder in two years ago after breaking his hand during the bout, was participating in his second appearance at light heavyweight.
By the fight's midpoint, the underdog had kept it close, creating difficulties for Buatsi, who worked behind a protective stance to edge the more effective rounds.
The audience's tolerance diminished during constant clinching, with Parker going down multiple occasions during clinches.
Parker ended stronger, but multiple periods were challenging to assess. Nevertheless, former world champion the boxing analyst - providing analysis for Dazn - had it significantly in favor for the challenger, scoring for Buatsi just only one stanza.
The victor advances, but with the presence of heavy hitter Benavidez, and Russian star Dmitry Bivol ruling the division, the path to championship success - judging by this showing - still looks steep.
Ricky Hatton Tribute Inspires Manchester Derby Fight
In the co-main event, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding all-Manchester battle to win the continental belt.
The venue became quiet for a extremely emotional homage before the fight as 10 bells sounded in honor of the city's native Hatton, who died 46 years old in recently.
It was the first major televised match card in the location since Hatton's passing. As the final chime disappeared, the silence became a chant of "there's just one Ricky Hatton".
The competition within the ring equaled the emotion. The eventual winner was sent to the canvas by a powerful punch flush on the chin in the early round, standing uncertainly to his feet on the eight count.
But the red-colored attire of Arthur soon advanced again. From the other corner, the opponent - in competitive blue - was injured quickly, noticeable damage developing under his face as the fighters landed punishing blows.
The challenger, twenty-seven, connected with strong blows but Arthur, thirty-four, matched the intensity with powerful upward punches as the pace rarely dropped over 12 rounds.
Arthur narrowly won the decision with judges scorecards of draw, narrow lead and clearer margin, but each competitor were persistent and courageous, exactly what their idol Hatton represented.
