Test and one-day cricket's greatest run-scorer approaches the game with undiminished enthusiasm and insists he has much to offer despite slipping from the dizzying heights he reached earlier in his 24-year career.
"People have been talking about my retirement since 2005, but that does not worry me at all," Tendulkar chided reporters at a promotional event in New Delhi last week.
"Your job is to write, my job is to play. I will stick to my job and you stick to yours."
Sachin Tendulkar plays a shot against Delhi Daredevils during the T20 match
Tendulkar, afforded almost religious status in India, burst onto the world cricket scene as a 16-year-old in 1989 and has played a record 198 Tests and 463 one-dayers, scoring an unprecedented 100 international hundreds. Know your Master Blaster
He was singled out by Don Bradman but the Australian legend's Test average is one of the few marks that Tendulkar has not been able to threaten, with his 15,837 runs coming at 53.86. Bradman averaged 99.94.
However, questions over his future mounted when he struggled for a year to score the ton he needed to take him to 100 centuries. He finally achieved the landmark against Bangladesh in Dhaka in March 2012.
Amul's tribute to the Master Blaster on his 40th birthday. (Credit: Amul)
Tendulkar, who decided not to play Twenty20 internationals after just one match in 2006, announced his retirement from one-day cricket last December in a bid to prolong his glittering Test career.
But his form in the five-day format has also dipped by his own stellar standards. He has scored just 1,145 runs in 21 Tests at an average of 31.80 since being part of India's World Cup-winning team two years ago.
And Tendulkar has not added to his tally of 51 Test centuries since making 146 against South Africa in Cape Town in January 2011.
But despite his struggles with the bat, the veteran is refusing to follow fellow modern greats such as compatriot Rahul Dravid and Australia's Ricky Ponting into retirement.
Sachin Tendulkar with Sunil Gavaskar. Getty images
Sunil Gavaskar, the first man to reach the 10,000-run milestone in Tests, suggested last year that Tendulkar's reflexes were on the slide. Former Australian captain Steve Waugh also feels he is past his best.
"He is not playing up to his standards," Waugh said last week. "But he himself has to decide (on retirement)." Sachin's coach Ramakant Achrekar speaks
A fan gives final touches to Sachin's sketch. PTI
When India succumbed to a Test series defeat against England at home in December, former skipper Sourav Ganguly backed calls for Tendulkar to quit.
"He is getting a long rope because of what he has achieved," Ganguly was quoted as saying by London's Daily Telegraph newspaper. "As somebody watching it from outside, Tendulkar is not performing.
"And I think if I were Tendulkar, I would go (retire)."
But Kapil Dev, another ex-India skipper, says Tendulkar is fit and hungry for success even after so many years of gruelling cricket. "Sachin passes on both counts. He could go on for years if he wanted to," he told AFP.
Six months ago, Tendulkar admitted in a television interview that retirement had crossed his mind, but said he would take it series by series before making a final call.
Kite maker Jagmohan Kanojia's dedication to Sachin Tendulkar. PTI
"I am 39-plus and it is not abnormal for me to think of retirement," he said. "I will go by what my heart says. At this moment, my heart says I am OK."
There has been speculation in the media over whether Tendulkar will play in India's next Test outing - a three-match away series against world number one side South Africa starting late in the year.
There is even talk of organising two home Tests against an unknown opponent before the tour of South Africa to enable Tendulkar to bow out with 200 appearances in a farewell series.
But few would be surprised if the player, described by former India coach Gary Kirsten as cricket's "greatest role model", bats on at the top level.
As many as 102 cricketers have played Test matches after hitting 40, the oldest being Englishman Wilfred Rhodes, who was 52 when he took on the West Indies in Kingston, Jamaica, in 1930.
Sachin Tendulkar, with the legendary Don Bradman's statue in the background. PTI
Tendulkar, who last year accepted a government offer to take up a nominated seat in India's upper house of Parliament, the Rajya Sabha, has never revealed what he wants to post-retirement.
"It is going to be hard because I have not experienced anything close to what I might go through when I retire," Tendulkar said in a recent television interview.
"I cannot relate this moment with any other moment in my life."
Cricketers salute Sachin ahead of his 40th birthday
Sachin Tendulkar's "insatiable hunger and incredible talent" has fetched him glowing tributes from fellow cricketers who say the batting great's longevity and passion for the game can never be surpassed.
Sachin Tendulkar after his century. Getty images
"Suffice to say, he is the greatest cricketer I have ever seen. I haven't seen Bradman, but he is as close to perfection as you can get. His insatiable hunger, combined with incredible talent, makes him a real genius. When people criticise him, all I point to them is the 100 international hundreds," Ganguly said in an article published in 'Outlook' magazine, which has brought out a special edition on the legendary batsman to commemorate his birthday.
Sri Lanka spin legend Muttiah Muralitharan said Tendulkar inspired him to play positively and aggressively.
"I saw the curly-haired cricketer for the first time in 1993. Soon after his debut a few years ago, he was the most spoken-about and discussed and was also touted as the next big thing in cricket. He was just 19 and I had not seen much of Sachin then. He didn't open the innings, he'd come out to bat at No. 5 in the one-dayers. Read more...
Kolkata fans plan a lavish birthday party for thier hero
Sachin may want muted celebrations of his 40th birthday on Wednesday but the city of joy is all set to throw a huge party for the veteran Indian batsman.
The Mumbai Indians batsman, who happens to in Kolkata on the special occasion for his T20 team's clash against Kolkata Knight Riders on Wednesday, will begin the day with a customary cake-cutting ceremony at the team hotel.
Tendulkar will cut a giant 40-pound chocolate cake specially ordered by the Cricket Association of Bengal in the lawn outside the dressing room.
Click on to know more about his b'day bash