UK light heavyweight Joshua Buatsi made a winning yet underwhelming debut to his career under recent management with a decision win over Parker in the Manchester arena.
The Olympic bronze medallist's punch output seemingly secured him a judges' verdict in a competitive ten-round fight at the boxing arena.
But the challenger landed significant shots, landing some telling individual punches in a match where the techniques failed to mesh, with excessive holding marring the contest.
The scoring judges judged it 96-94 for to the winner, with the final judge a 95-95 draw.
"It wasn't my greatest display but what defines champions? They succeed," Buatsi commented in the ringside as he was met by disapproval from the audience.
The British fighter returned to winning ways after his initial pro loss - an thrilling contest with his previous opponent in last winter - to earn a 20th career victory.
Various analysts felt Parker, thirty-one, deserved the victory but the contender suffered the second loss of his 28-bout career.
Buatsi Secures Victory in Slow Match
His career development has slowed in recent times through management issues and extended periods of lack of fights.
Once tipped as the rising talent of UK boxing, he now stands trying to achieve expectations - possibly in what appears to be a final roll of the dice - under recent support.
He began cautiously, with both competitors willing to overcommit in a cagey opening few rounds.
The challenger, whose single earlier setback came at the lower weight class against his former opponent in 2022 after damaging his hand mid-fight, was making just his second bout at light heavyweight.
By the halfway stage, Parker had made it competitive, causing problems for the favorite, who utilized a tight guard to edge the more effective rounds.
The audience's tolerance decreased during constant clinching, with Parker going down various instances during clinches.
The underdog ended stronger, but multiple periods were challenging to assess. Although, former world champion Carl Frampton - commentating on Dazn - had it significantly in favor for the challenger, giving Buatsi just a single round.
The victor advances, but with the caliber of power puncher Benavidez, and Russian champion Dmitry Bivol dominating the weight class, the journey to titles - on this evidence - still looks steep.
Hatton Tribute Fuels All-Manchester Contest
In the co-main event, Arthur defeated Rea by close verdict in a terrific local rivalry fight to win the European light heavyweight title.
The stadium fell silent for a deeply poignant tribute before the fight as 10 bells rang in remembrance of Manchester's own Hatton, who passed away at age 46 in recently.
It was the first major televised match card in the city since Hatton's death. As the final chime disappeared, the quiet became a chant of "there's just one Hatton".
The competition during the bout matched the emotion. Arthur was sent to the canvas by a left hook directly to the chin in the early round, getting up unsteadily to his feet on the referee's count.
But the Manchester United-red shorts of Arthur soon pressed ahead again. Across the ring, Rea - in rival City blue - was injured early, heavy swelling appearing under his eye as the fighters landed hard punches.
Rea, twenty-seven, connected with strong blows but the champion, 34, responded in kind with powerful upward punches as the action hardly diminished over 12 rounds.
Arthur narrowly won the verdict with scoring tallies of draw, close margin and clearer margin, but the two athletes were persistent and full of heart, everything their idol the legend embodied.
