Former Socceroo skipper and defender Craig Moore, who will join coach Ange Postecoglou's national team staff as a player mentor during the World Cup, knows from first-hand experience the truth of the old saying.

Moore is hoping his background as a player and his experience of the highs and lows of the game will be an invaluable asset to an Australian squad likely to be crammed full of young and relatively inexperienced players during the high pressure environment of the World Cup in the game's spiritual home, Brazil.

Reflecting on his own career, Moore recalls a night in Amsterdam when, as a 21-year-old, he was playing for Glasgow Rangers against Ajax in a Champions League game. Teammate Paul Gascoigne had been sent off, the Rangers side was reshuffled, and Moore was stationed at right-back where he had to mark Dutch flyer Marc Overmars.

''I was a young player, they [Ajax] were the best team in Europe at the time. It was my worst night of football -  I saw the back of his heels the whole bloody night,'' he said. "But the lesson it taught me was invaluable. I knew how to deal with that situation if it happened again.''

The experience made him a better player.

''Your worst moments can be invaluable in regards to your career, as it's a great learning lesson,'' he said.

Moore says his job with the Socceroos will be to help the more inexperienced players retain perspective during the tournament.

''We had a lot of good nights with the national team, and some disappointing nights as well. The game has changed, there's a real added responsibility in how you carry yourself, as someone who is representing your national team.

"That's changed a lot from my day, when that profile wasn't there, and now you can't really move and you have to be very careful about what you do on the field and more importantly what you do off the field.''

Moore will be with the team during the lead-up and throughout the tournament, someone the coaching staff can bounce ideas off and, crucially, a shoulder to lean on for the players.

Postecoglou, who ended Moore's career at Brisbane Roar when he took over during the 2009-10 season, was the one who sought Moore out and asked for the position to be created.

At the World Cup draw in Brazil in December, he saw that many of the most successful nations had former star players working with national teams in mentoring roles, and felt it was something Australia could replicate.

"We've been to the two most recent World Cups and we have players who have had that experience, it would be foolish for us not to take someone along who had experience of that and an understanding of what's going to happen,'' Postecoglou said.

''He had experience in the media too and I wasn't necessarily looking for someone who was coaching.''

Asked whether it had been difficult to patch things up with Moore after what had happened at the Roar, Postecoglou said it was never an issue.

''It is never personal with me, I just make decisions that I think are good,'' he said. "I was never making a judgment on his career or him as a person - I was making judgments on what I thought was best for the football club.''

Moore concurred, saying that Roar's season had finished and, in the early months of 2010 he had to leave Australia and find a club to play for anyway as he needed to retain fitness for the World Cup in South Africa later that year.

''I have spoken to Ange a number of times over the years. The biggest problem for me at that time was the way it was reported through the media. There was no real issue. We are both really passionate about the game and we want to see Australia improve.

''I will bring support in helping the players gain confidence. The rewards are massive for the future.''