"He just said to keep working hard and as long as you're putting the work in you'll reap the rewards," Kamau told The World Game.
"You can realise your ambitions, but only if you want to work for them."
Hard work is how Cahill made it to the top and why he is still playing at 36, so a more complex message just to make it sound spectacular would be short-changing his team-mate.
More than anything it's seeing Cahill put his words into practice that Kamau has taken the most from.
"It's just the way Tim goes about his business," he said.
"He has come here very serious about playing football and playing well and winning, so it's about the great attitude he has. You can take a lot out of that."
Kamau left Adelaide United at the end of last season, having won the Premier's Plate and A-League championship with them, in the knowledge he was going to keep playing with great players at City.
Then, in a huge bonus Socceroo superstar Cahill joined the club.
Kamau said the experience had been mind-blowing for him.
"Coming here I knew Bruno (Fornaroli) was at the club and he's a fantastic player, and Luke Brattan as well, he's going to be great for the club, and then to have Tim come in on top of that was a big surprise, a very pleasant surprise," he said.
"He has brought his experience and a presence to the change-room. He has played at the highest level, so everyone is going to respect his opinion.
"For me, personally, it's fantastic to have someone like Tim in the same team, especially when I'm so young.
"To be able to play with arguably Australia's greatest player and get advice from him is only going to better my game and help the team as well."
The A-League round starts early this week, with City hosting Newcastle Jets at AAMI Park on Thursday.
City are trying to bounce back from a 1-0 road loss to Brisbane Roar.
"We've worked on the things we needed to work on and now we'll go out there with the aim of rectifying the result from last week," Kamau said.
"If we do what we need to do and know we can do, I don't think there's any team we can't beat."