Australia Test captain Michael Clarke says retiring Indian batting legend Sachin Tendulkar's greatest achievement is playing international cricket for almost a quarter of a century.
Clarke said Tendulkar, who is playing in his 200th and final Test, ranked second only to Australia's Don Bradman as the best batsman of all time.
The 40-year-old is ending an international career which began in 1989 and during which time he became the all-time leading Test and one-day batsman and the only man to score 100 international centuries.
"So much has been said and written about Sachin's achievements over years," Clarke wrote in The Daily Telegraph on Friday.
"His record number of Test and one-day runs, his century of international centuries. They are achievements that may never be bettered.
"However I believe his greatest achievement is playing international cricket for almost a quarter of a century. That is phenomenal. To be lining up for his 200th Test is mind boggling.
"It highlights an undying affection for the game that goes way beyond just playing."
Clarke, who will lead Australia in five Ashes Tests against England getting underway in Brisbane next week, said Tendulkar had been the greatest constant in world cricket for a generation.
"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," he said.
"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."
Clarke said Tendulkar ranked as the second best batsman behind the "incomparable" Bradman.
"I've been lucky enough to play with and against some great batsmen but there have been none better than Sachin in my time," he said.
"Given everything he has done, Sachin would have to be the second best batsman of all time after the incomparable Bradman.
"You would never know it speaking to him."