Clarke, who is set to lead Australia in the Ashes series starting in Brisbane Nov 21, said he was amazed at Tendulkar's career which began with the tour of Pakistan in 1989.
"I was still at primary school when he began his Test career and later scored two centuries on his first tour of Australia as an 18-year-old," Clarke recalled.
"I played my first Test series against him almost a decade ago and through my whole career have never really thought about him as an ageing player. I can't believe he is 40."
"Sachin has done it all, carrying an unimaginable weight of expectation."
