"Liam adopted him, through the pre-season when Sione was never quite up to shape. The friendship grew and grew, and they became very tight."
Foster said Lauaki brought a flair which allowed the Chiefs to flourish, while he also acknowledged the widely held view that Lauaki did not live up to his gifts.
"He was gold for us - we had a lot of really hard working diligent type rugby players and this guy turned up...a flawed genius," recalled Foster.
"He never trained quite as hard as he needed to. Nick Gill was our trainer at the time and he was almost full time getting Sione fit.
"(but) he helped change the whole way we played and turned us into an open, fast, exciting team at the time."
On the subject of falling short of potential, Foster said: "Everyone is going to say that, and it is largely true. He never really pushed himself as hard as what he could off the park to be the best on the park
"But there were moments each year when you just couldn't stop him. Most people have unique memories of him demolishing opponents almost single handedly. He just wasn't able to do it the next week and the next week.
"Let's celebrate the great moments - he had plenty - and acknowledge that for him the hard work side of the game wasn't easy."
Foster said Lauaki's illness problems had been a long-standing battle, but news of his death came as a shock.