The Joeys will face Indonesia in the last eight on Monday night.
Should they win that match they will not only be through to the semi-finals but also qualify for the Under-17 FIFA World Cup in Peru next year.
Former Socceroos defender Robbie Cornthwaite, now based in Malaysia, was in attendance for the victory and said the young squad can expect an intimidating atmosphere for their next match.
"Let me tell you there will be at least 5-10,000 Indonesian fans minimum for the clash! These young boys are about to experience a very hostile environment," Cornthwaite tweeted.
The Joeys started brightly with an early goal from Joseph Roddy, who is on the books at Sydney FC.
Things went from bad to worse for Afghanistan when their goalkeeper was sent off in the 17th minute after a second yellow card, this one for a clear handball outside the box.
Australia took full advantage of the extra man, doubling their lead through Noah Botic who tapped home a low cross from Roddy.
Roddy made it 3-0 just before half-time before Botic grabbed his brace to make it 4-0 midway through the second half.
It was a solid performance from Trevor Morgan's side who looked in control the whole match.
