India will define their place in cricket history over the next 18 months with tours of South Africa, Australia and England putting them to the test, the team's coach said Wednesday.
The world's number one ranked Test side have become invincible at home since losing a one-day and T20 series to South Africa in 2015.
In a landmark tour of South Africa next month they are looking for a record 10th straight Test series win. They are currently level with Australia on nine straight series wins.
Shastri and captain Virat Kohli said the side are ready for the challenge, which will be followed by tours of England and Australia and then the World Cup.
Shastri stressed the importance of building the same squad around Kohli since the last tour of South Africa in 2013.
"This one and a half years will define this Indian cricket team, and the whole team is aware of that.
"All I can say is that this will be a better cricket team after those 18 months."
Kohli said the team is stronger than the last tour to South Africa when the Proteas won the two-match Test series 1-0.
"The bowling has come a long way, the batting has come a long way, all the guys are much more experienced now, but the hunger remains the same. We still want to go back and try to do what we couldn't do the last time."
The captain and star batsmen said India have been "relentless" in their performances against Sri Lanka, New Zealand, Bangladesh and England over the past year.
India's players have also taken "beautifully" to changes he has introduced with Shastri to increase discipline, Kohli said.
India play three Tests, six one day internationals and three T20 games in South Africa. The first Test starts in Cape Town on January 5.