Australia's batsman Matt Renshaw steers a ball to leg from the Pakistan bowling during the first day of the third cricket Test match at the SCG in Sydney on January 3, 2017. WILLIAM WEST/AFP/Getty Images

Young Australian opener Matt Renshaw's Test career has started in prolific fashion.

The 20-year-old hit a blistering 184 in just his fourth Test match and now he has broken a long standing Aussie record.

Renshaw passed 500 Test runs yesterday, with his knock of 44 in Australia's first innings in the third Test against India.

In doing so, he became the first Australian batsman to reach 500 Test runs before the age of 21.

“The way he played - he hadn't actually hit the ball that well in our lead up - but for some reason when he gets out in the middle, he knows exactly what he wants to do and how he wants to do it,” Australian coach Darren Lehmann said.

“So for a 20-year-old that's pretty special.

“For him to come out, obviously a bit crook here and there, and to bat in different positions and have a clear plan, especially in the second innings, about the way he wanted to go about it, that's good for a young man to have that insight into the game so early.”

Renshaw has now played six Tests, hitting three half-centuries and one century with an average of 53.22.