UK light heavyweight Joshua Buatsi made a winning yet unimpressive start to his career under recent management with a unanimous decision over Parker in the Manchester arena.
The Olympic bronze medallist's activity level likely gained him a majority decision in a tight ten-round contest at the Manchester venue.
But Parker found success, delivering effective clean blows in a match where the styles never quite clicked, with frequent clinching marring the action.
Two judges had it 96-94 in favor to Buatsi, with the final judge a 95-95 draw.
"It wasn't my finest display but what do champions do? They succeed," Buatsi stated in the ringside as he was met by disapproval from the spectators.
The Londoner bounced back after his maiden career setback - an epic battle with his previous opponent in last winter - to earn a twentieth professional win.
Several boxing experts thought Parker, 31, merited the win but the contender endured the second setback of his 28-match career.
Buatsi Claims Victory in Slow Match
His career development has stalled in the past few years through management issues and considerable time of inactivity.
Earlier forecast as the future of British boxing, he now is positioned trying to realize his potential - maybe in what seems like a last chance - under recent support.
He started carefully, with the two boxers ready to take risks in a calculated opening few rounds.
The challenger, whose only previous defeat came at super middleweight against John Ryder in two years ago after breaking his hand during the bout, was competing in only his second appearance at light heavyweight.
By the halfway stage, Parker had made it competitive, making life awkward for Buatsi, who utilized a protective stance to edge the cleaner stanzas.
The spectators' acceptance wore thin because of frequent holding, with the challenger going down multiple occasions during close exchanges.
Parker ended stronger, but several stanzas were difficult to score. Nevertheless, former world champion the boxing analyst - working with the broadcast network - had it strongly leaning for Parker, scoring for Buatsi just one round.
Buatsi progresses, but with the presence of power puncher David Benavidez, and Eastern European fighter Dmitry Bivol ruling the division, the road to world glory - on this evidence - still looks steep.
Hatton Memorial Motivates Local Rivalry Fight
In the secondary fight, Arthur overcame Rea by divided decision in a terrific all-Manchester battle to secure the European light heavyweight championship.
The venue grew hushed for a extremely emotional memorial before the fight as 10 bells tolled in honor of local hero Hatton, who succumbed at age 46 in September.
It was the initial significant broadcast match card in the location since Hatton's passing. As the concluding sound ended, the stillness transitioned to a roar of "only one Ricky Hatton".
The action inside the ropes equaled the feeling. Arthur was sent to the canvas by a left hook squarely on the face in the early round, rising shakily to his feet on the referee's count.
But the red-colored attire of the fighter soon came forward again. On the opposite side, Rea - in rival City blue - was damaged quickly, significant bruising forming under his face as the fighters traded powerful shots.
Rea, twenty-seven, connected with strong blows but the champion, thirty-four, fought fire with fire with stinging uppercuts as the action seldom decreased over 12 rounds.
Arthur narrowly won the decision with judges scorecards of draw, narrow lead and clearer margin, but each competitor were persistent and full of heart, exactly what their inspiration the legend stood for.
