British light heavyweight Joshua Buatsi secured a victory yet disappointing start to his career under new promoters with a decision win over Parker in the Manchester arena.
The Olympic medal winner's activity level seemingly secured him a majority decision in a competitive 10-round contest at the Manchester venue.
But Parker had his moments, connecting with powerful clean blows in a match where the approaches failed to mesh, with excessive holding marring the contest.
The officials had it 96-94 to Buatsi, with the remaining official a 95-95 draw.
"It wasn't my greatest performance but how do champions respond? They prevail," the victor stated in the arena as he was greeted with disapproval from the crowd.
The British fighter bounced back after his initial pro loss - an epic battle with his previous opponent in last winter - to earn a 20th pro success.
Several boxing experts thought the challenger, 31, deserved the victory but the British boxer suffered the second setback of his 28-bout career.
Buatsi Earns Win in Slow Affair
Buatsi's progress has stalled in the past few years through contract problems and considerable time of inactivity.
Previously predicted as the rising talent of UK boxing, he now stands trying to fulfil that early promise - maybe in what appears to be a last chance - under fresh management.
He began cautiously, with neither fighter prepared to take risks in a cagey opening few rounds.
The challenger, whose only previous defeat came at the lower weight class against his former opponent in two years ago after breaking his hand during the bout, was making just his second appearance at light-heavyweight.
By the middle rounds, the underdog had kept it close, causing problems for the favorite, who utilized a tight guard to edge the more effective stanzas.
The spectators' acceptance diminished during regular grabbing, with Parker falling to the floor various instances during clinches.
Parker closed well, but multiple periods were hard to judge. Nevertheless, ex-champion Carl Frampton - commentating on Dazn - had it strongly leaning for the challenger, awarding Buatsi just a single round.
Buatsi progresses, but with the likes of hard hitter David Benavidez, and Russian champion Bivol ruling the division, the road to world glory - judging by this showing - still appears challenging.
Ricky Hatton Homage Motivates Manchester Derby Contest
In the secondary fight, Lyndon Arthur beat Bradley Rea by split-decision in a outstanding local rivalry contest to secure the European light heavyweight championship.
The stadium became quiet for a deeply poignant tribute before the fight as 10 bells rang in memory of Manchester's own Hatton, who succumbed aged 46 in recently.
It was the premier televised fight night in the city since Hatton's passing. As the last bell disappeared, the quiet became a shout of "there's only one Hatton".
The action inside the ropes matched the sentiment. The eventual winner was knocked down by a significant blow directly to the jaw in the early round, standing uncertainly to his feet on the count of eight.
But the red-colored equipment of Arthur soon pressed ahead again. From the other corner, Rea - in opposing blue - was injured soon, heavy swelling forming under his eye as the pair exchanged punishing blows.
The challenger, 27, landed power punches but the champion, thirty-four, responded in kind with powerful upward punches as the action seldom decreased over twelve rounds.
Arthur narrowly won the result with scoring tallies of 114-114, narrow lead and clearer margin, but each competitor were relentless and brave, everything their inspiration Hatton represented.
