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Adam Ashley-Cooper says the tragic death of a former team-mate and leading Sydney referee is a poignant reminder of just how fortunate he is to vice-captain the Wallabies in pursuit of Rugby World Cup glory.

Guy Grinham, who grew up playing with and against Ashley-Cooper, died this week at just 31 after battling cancer. But the father-of-two lived out one final dream last Saturday when he watched on from the stands at Twickenham as Ashley-Cooper starred in Australia's epic Pool A-deciding win over Wales.

Ashley-Cooper climbed deep into the famous stands to celebrate with Grinham and says his friend's plight "puts life into perspective".

"We are very lucky. It is truly a sad story but it was awesome to share that moment with him after the game," Ashley-Cooper told AAP. "His wife told me that he spoke to her about how happy he was from being at the game and being part of that win before he would finally be at rest."

Ashley-Cooper told Fairfax Media Grinham had been diagnosed with cancer just over a year ago and he had quickly put together a bucket list, with watching the Wallabies at the World Cup top of the list.

"A year and a half ago he was diagnosed with cancer, and just recently he was given a brief amount of time to live," Ashley-Cooper told Fairfax Media. "Along with the help of his brother and best mate, he put together a bucket list. And on that bucket list was to watch the Wallabies at the World Cup.

Beautiful & heartbreaking: Ashley-Cooper farewells mate who passed away at #RWC pic.twitter.com/XVGjhS5OaG

— Emily Benammar (@EmilyBenammar) October 16, 2015

"He was on his way over to watch but when he got off the plane he went downhill significantly. The cancer spread into his vertebrae, so he had to get to hospital. The nurses told him to ring his parents about coming over to give them their final goodbyes, because he didn't have much time left.

"We organised a signed jersey, and I went and saw him in hospital [before the match against Wales]. We talked about playing footy when we were younger, and what the Wallabies were doing, instead of talking about the position he was in."

Grinham passed away just days later, but when Wallabies coach Michael Cheika learned of the heartfelt story he asked the winger to share the story with the team at training.

"Cheik got us together this morning and asked to take a moment in silence and to really think about a bloke who was suffering so much, and yet on his bucket list was to come over and watch us play, and just the fight that he had to go through to get to the game," Ashley-Cooper told NewsCorp.

Ashley-Cooper, 31 like Grinham, will surpass the great George Smith as Australia's third-most-capped player when the Wallabies take on Scotland on Sunday night (2am Monday AEDT) for a place in the World Cup semi-finals.

Only 1999 World Cup-winning captain George Gregan, with 139 caps, and Nathan Sharp (116) have played more Tests than Ashley-Cooper, who will be wearing the gold jumper for the 112th time.