Former India coach Greg Chappell, in a new book, has claimed that cricket icon Sachin Tendulkar was "mentally fragile" at a certain stage of his illustrious career and was beset with "self-doubt".

Chappell, who had a controversial three-year stint as India coach from 2005-07, claimed in his new book Fierce Focus that Tendulkar's mental state had been "surprisingly fragile" in 2006.

"At one point early in my time with the (Indian) team ... he came and talked to me for about two hours," Chappell wrote in his new book, a brief extract of which was published in the Herald Sun.

Chappell, who was sacked a few months back as Australia's national selector apparently after a fall out with senior cricketers, suggested that Tendulkar could have been affected by the weight of expectations.

"When the team travelled, he would snap on his headphones, not look sideways, and shut it all out. Not even Don Bradman carried expectations like this, and Sachin had been bearing it since 1989," Chappell said in the book.

"He just couldn't get any rest. Once we were talking ... and I said, 'You must have so many friends, it must be hard finding time to keep in touch with all of them'. He looked me in the eye and said, 'Greg, you would have more friends in India than I've got'," Chappell said

Chappell's views on Tendulkar came barely two months before what could be the Indian maestro's farewell four-Test tour of Australia this summer.