Williams showed patches of brilliance but also made two big errors in the final before being replaced which almost cost his team the title.
"He (Williams) said it was tough and he said he is still a rookie," Cooper said.
"I watched a few of his games and saw how well he went in patches - it's like anything, you learn as quick as you can and you adapt as fast as possible.
"There is still so much learning to do and I think for both myself and him it's very similar to boxing.
"When we started boxing we knew very little, and still do, but we put ourselves in that position to learn and that is where the challenge comes - in just being able to learn on the run."
Australian Sevens coach Andy Friend couldn't guarantee Cooper will get much playing time at this weekend's event, where the Australians will be desperate to impress before sell out home crowds.
He also stressed Cooper would not be a walk-up start in the side in the lead up to Rio despite the great efforts the Australian Rugby Union has gone to secure his limited release from Toulon.
Unlike Cooper, Williams has committed fulltime to New Zealand's sevens programme, skipping Super Rugby this season, as he adapts to the game.
- AAP