The 38-year-old, who is a 2012 Olympic bronze-medallist, prevailed 4-1 against a rival who is 15 years her junior and a Pan American Games bronze-medallist.
"There was a ban on eating ice creams on you during the 2016 Olympics, has another ban been imposed for Tokyo," he asked to a grinning Sindhu, who would be aiming to better the silver she won five years ago.