Teenage whiz kid Sam Konstas will become the youngest-ever man to open the batting for Australia in Test cricket, coach Andrew McDonald has confirmed.

Konstas will also become the fourth-youngest Test cricketer to play for Australia and the youngest since captain Pat Cummins on Thursday, when he replaces axed opener Nathan McSweeney at the top of the order.

The 19-year-old batted at the Melbourne Cricket Ground nets again on Tuesday as the Australian team prepares for the crucial fourth Test.

“He’s been very similar to what I’ve seen on the outside … he’s composed, relaxed,” McDonald said.

“He’ll play Boxing Day, so I’ll get that one out of the way.

“What he’s shown is an array of shots and an ability to put pressure back on his opponents.”