Tanveer Sangha arrived in South Africa with a handful of List A matches to his name but on Wednesday the young legspinner shot into the Cricket World Cup selection frame with a stellar, four-wicket debut for Australia.

The 21-year-old's haul helped Australia crush the Proteas by 111 runs in their opening Twenty20 match in Durban as Mitchell Marsh celebrated his captaincy debut with an unbeaten 92 from 49 balls.

Sangha, the son of Indian immigrants, has been watched closely by Australia's selectors since claiming 21 wickets for Sydney Thunder in the 2020/21 Big Bash League as a 19-year-old prodigy.

That earned him a place in the T20 squad for the New Zealand tour in 2021 but he had to wait longer than expected for his international debut due to a back stress fracture that wiped out his 2022/23 season.

When his chance eventually came in Durban he grabbed it with both hands.

"It was great to see Tanveer. He's a ripping young kid," Marsh told reporters. "He'd got off the plane yesterday and wasn't playing until this morning.

"He was very calm .... What we've seen him do in the Big Bash, tonight was no different.

"So it's great to see someone like him, his mindset and not being, I guess, nervous to come out here.

"I mean, I'm sure he was nervous but you couldn't tell.

"The way he bowled was outstanding and as for everyone else they all contributed."

Sangha's maiden international wicket was a gift as South Africa captain Aiden Markram (7) cut a short and wide delivery straight to Marcus Stoinis at backward point in the seventh over.

Two overs later Sangha had fellow debutant Dewald Brevis out for five slogging to long-off, then wicketkeeper Tristan Stubbs stumped for a duck on the next ball.

He finished with 4-31 after bowling Marco Jansen for 20 and walked off the ground after the victory was completed with delighted teammates patting his head.

Named in Australia's preliminary squad for the 50-overs World Cup starting in October, Sangha may struggle to edge out Adam Zampa and Ashton Agar from the final 15 but could be included if selectors opt for a third spinner on India's dry pitches.

Left-arm pace bowler Spencer Johnson also enjoyed a fruitful debut for Australia in the absence of Mitchell Starc, wrapping up the win by dismissing opener Reeza Hendricks for 56 and tail-ender Tabraiz Shamsi (0) in quick succession.