Now that Parker and his team have the respect of the Klitschko camp, more opportunities are likely to arise, including training camps and fighting on Klitschko's undercard.
Klitschko told of sparring with Parker to Rafael: "I like to have actual boxers competing in there when we spar, guys who want to become champions, guys who bring that attitude to the ring. We've had some intense sparring. He has given me great work, exactly what I need."
Klitschko's comments were a boost for the Parker camp and his promoters Duco, but for Barry the training which preceded them was more important.
"Being competitive in a sparring situation with the No1 heavyweight in the world has to give a young fighter like Joe a ton of confidence and self- belief," Barry said.
"The sparring with Klitschko was very physical. Klitschko is a big, powerful, strong guy and he spars at a very high intensity. His level of fitness and discipline is superior to every other heavyweight in the world and that was very evident early. He has perfected his own style.
"Joe and Izu sparring with him was like doing a puzzle, figuring out how to unlock his defences.
"Klitschko made a huge impression on them. It was a great experience for them to watch him at work - the way he manages his affairs - his work ethic, which is second to none, and his attention to detail is unequalled. He's such a great role model for up-and-coming heavyweights. We appreciated the opportunity and I believe we made the most of it."
An example of Klitschko's attention to detail is his 40-minute stretching sessions before training.
"As much as Joe stepped up to the challenge - and he has come a very long way in the last two years - it's very clear we still have a long way to go," Barry said.
Parker's last fight was last month, a straightforward fourth-round knockout against Jason Pettaway in Manukau. His next fight is likely to be more of a challenge and that is likely to suit Parker, who seems to excel more against men with power and ability.
His speed and power have been highlighted more in his knockout wins over fighters such as Frans Botha, Brian Minto and the previously undefeated Brazilian, Irineu Beato Costa Junior.
After the Klitschko sessions, his preparation is likely to go to the next level.
"Joe arrived back in Vegas very pumped up and motivated. I believe he now has a more realistic expectation of the level he needs to be at," Barry said.
"He's more inspired and determined to take his boxing to the next level. That's one of the main things I was wanting to achieve by attending this training camp."
