British light heavyweight Joshua Buatsi earned a win yet underwhelming beginning to life under recent management with a unanimous decision over Parker in Manchester.
The Olympic medal winner's punch output appeared to earn him a majority decision in a competitive 10-round contest at the Manchester venue.
But the challenger found success, landing some telling individual punches in a fight where the approaches failed to mesh, with constant grabbing marring the contest.
Two judges had it 96-94 in favor to the winner, with the final judge a even score.
"It wasn't my finest performance but what defines champions? They succeed," the victor stated in the ring as he was met by negative reactions from the crowd.
The British fighter got back to winning after his first professional defeat - an thrilling contest with his previous opponent in last winter - to earn a twentieth professional win.
Various analysts thought Parker, 31, should have been awarded the victory but the British boxer endured the second loss of his 28-bout career.
Buatsi Claims Win in Slow Affair
His career development has plateaued in recent times through contract problems and considerable time of lack of fights.
Once tipped as the rising talent of British boxing, he now finds himself trying to achieve expectations - possibly in what appears to be a ultimate opportunity - under new promotional backing.
He began cautiously, with neither fighter prepared to be aggressive in a cagey early stages.
Parker, whose sole prior loss came at the lower weight class against John Ryder in two years ago after suffering a hand injury during the bout, was competing in only his second fight at the higher weight class.
By the middle rounds, the underdog had kept it close, causing problems for Buatsi, who operated with a solid defense to edge the better rounds.
The audience's tolerance decreased during constant clinching, with Parker going down various instances during close exchanges.
Parker closed well, but several stanzas were challenging to assess. Nevertheless, former world champion the boxing analyst - working with Dazn - had it particularly wide for Parker, scoring for Buatsi just a single round.
Buatsi moves on, but with the presence of heavy hitter Benavidez, and Eastern European fighter Bivol dominating the weight class, the path to championship success - on this evidence - still seems difficult.
Ricky Hatton Memorial Motivates Manchester Derby Battle
In the secondary fight, Arthur beat Bradley Rea by split-decision in a terrific local rivalry battle to win the European light-heavyweight belt.
The arena became quiet for a profoundly moving homage prior to the bout as ten bells rang in honor of the city's native Ricky Hatton, who died aged 46 in September.
It was the premier televised boxing event in the city since the passing of Hatton. As the final chime faded, the stillness became a shout of "only one Ricky Hatton".
The competition inside the ropes matched the emotion. Arthur was floored by a significant blow flush on the face in the early round, getting up unsteadily to his footing on the count of eight.
But the red-colored attire of the fighter soon pressed ahead again. From the other corner, the opponent - in competitive blue - was damaged soon, noticeable damage developing under his orbital area as the fighters landed hard punches.
Rea, 27, connected with strong blows but the champion, thirty-four, responded in kind with powerful upward punches as the action seldom decreased over twelve rounds.
The victor edged the result with official scores of draw, 115-113 and wider gap, but each competitor were persistent and brave, everything their hero the legend embodied.
