The Kiwis missed their chance of lifting the World Cup trophy at the Lord's balcony due to inferior boundary count after both the 50 overs and the Super Over ended in ties.
Shastri, praised Williamson, saying the Kiwi skipper's silence since the World Cup final is remarkable.
Widely praised for the grace with which he and his side accepted the defeat, Williamson said they had signed up to the rules that governed the tournament.
Eoin Morgan lifted the World Cup as England won for the first time the coveted trophy at the hallowed Lord's in London.
New Zealand lost to England in perhaps the greatest World Cup final at the Lord's on Sunday due to inferior boundary count.
After England's side finished on 241 all out in pursuit of New Zealand's 241-8, the final came down to a six-ball shootout for each team.
New Zealand scored 241 for eight after opting to bat first and England managed the same to send the game into a super over.
For the second successive World Cup, New Zealand enters the final as the underdogs.
A scribe told him that he met angry Indian fans outside the stadium after their semi-final loss and his reply, filled with warmth, could win hearts instantly.
Kane Williamson and the Kiwis focussed on getting to 240-250 before banking on their formidable bowling attack.
The soft-spoken New Zealand skipper acknowledged that it was tough for any side to recover from 24 for 4 to which India were reduced to in the 10th over.
In the round-robin stage, two-time champions India's match against New Zealand was a washout. But the rain stayed away from Manchester on the reserve day of the World Cup semifinal.
The two star batsmen first encountered each other in youth cricket, with Kohli -- an occasional medium-pacer -- taking Williamson's wicket via stumping.
India skipper Virat Kohli, whose team chased down 265 in their last group game against Sri Lanka at Headingley on Saturday, said handling pressure is key to batting second.
It couldn't have been more enticing that Rohit (647), KL Rahul (360) and Virat Kohli (442) with a cumulative contribution of 1347 runs will meet their match in Ferguson, Boult and Henry.