Joshua won his first three belts by stopping Ukrainian Wladimir Klitschko at London's Wembley Stadium in April a year ago, with 90,000 fans celebrating one of the great nights for British boxing. True champion. @anthonyfjoshua, I ACCEPTED 100% .
Both fighters were undefeated before the contest, but Joshua weighed in six pounds heavier than his shorter opponent and had a longer reach.
Parker's raiding attacks continued to unsettle AJ, who was forced to hold in the ninth, but Joshua's spiteful work opened a cut over his foe's eye in the 10th.
Despite taking out all three scorecards by a comfortable margin, England's Joshua faced one of the toughest tests of his career so far, taken through all 12 rounds for the first time in his 21 professional bouts.
Joshua wasn't interested in a face-to-face confrontation with Wilder following Saturday's fight.
The Brit's win means he now moves one step closer to being the undisputed heavyweight world champion, needing just Deontay Wilder's WBC belt to add to his IBO, IBF, WBA and WBO titles. "I said it will be finesse and I stuck to my words".
"I would love to maybe go to America with Eddie and Rob (Joshua's trainer Rob McCracken) and look at the landscape and deal with this behind closed doors".
Joshua appeared relaxed as he walked to the ring in front of a sell-out crowd approaching 80,000, while Parker also lapped up the occasion during his entrance before both fighters got down to business and protected unbeaten records. "As the saying goes, a good right hand can take you around the block, but a good jab can take you around the world".
Joshua said: "I am not elated because I don't let the highs get to my head".
"Today I got beat by a better champion, the bigger man", the 26-year-old said, speaking to Sky Sports.
Hearn, meanwhile, added: "I think it (Wilder fight) has to happen in 2018 otherwise we are going to hit some major problems with the politics and the mandatories". No regrets. Take it on the chin.
"He (Joshua) is a good big man and was better on the day".