From selling street food in Mumbai to winning the player-of-the-match award in his test debut in Roseau, India opener Yashasvi Jaiswal is international cricket's latest rags-to-riches story.

India thumped West Indies by an innings and 141 runs inside three days, a victory set up by Jaiswal's 171, which helped the visitors rack up 421-5 before they declared their innings.

It was a stellar display by the 21-year-old from Uttar Pradesh, who moved to Mumbai when he was 12. There he would sell 'pani-puri', a traditional Indian snack, for pocket money and sleep in tents until a coach took him under his wing.

The left-handed batsman has impressed in domestic cricket and was adjudged player-of-the-tournament in the Under-19 World Cup in 2020 after which Rajasthan Royals splashed out 24 million Indian rupees ($292,508) to sign him for the Indian Premier League.

With India looking for a left-right combination at the top, especially after Shubman Gill requested to move down to number three, Jaiswal was picked to partner captain Rohit Sharma and the debutant impressed immediately at the Windsor Park.

"I used to think about playing for my country when I was young," Jaiswal said after collecting his player-of-the-match award.

"Emotional moment for me but this is just the start."

"A lot of people have helped me in this journey. I want to thank each and everyone...I want to thank the selectors and captain for showing faith and allowing me to express."

Rohit said he never doubted Jaiswal's talent and, during their opening partnership, kept telling the debutant that he belonged at the test level.

"We knew about it (his talent). He's shown us in the past couple of years that he's ready for this big stage," Rohit said.

"He came and batted sensibly, showed a lot of patience, and the temperament was tested as well."

"In the middle, it was just about having a chat, letting him know, 'You belong here.'

"That is the most important thing, because when you're playing your first test match, you kind of keep asking yourself whether you belong here or not."