It was ugly at times, it was messy at times, it often made no sense.

But by the time the final whistle was blown, Australia and Great Britain had played out an all-time classic.

The 4-3 win for the Matildas after extra-time looks impressive enough on paper, but it's hard to describe just how gutsy a performance it was, in a game that developed from a trudge to a thriller over 120 minutes.

It was the best Matildas win in years and it means they are in the semi-finals of the Olympics for the first time. They're one win away from a medal and two from gold.

And this was the victory Tony Gustavsson's side needed to prove they can beat the best, two years out from a home World Cup. 

Friendly wins against the US or Brazil are one thing, but beating Britain in a high-stakes slug-fest is big time.

It was a bizarro game, in which almost every goal came against the run of play.

Initially it looked like the Matildas were completely outmatched by the favoured Brits, who pegged them back against their own goal in the opening stages and created a number of excellent chances which they just couldn't put away.

Aussie keeper Teagan Micah and the woodwork both had claims for player-of-the-match for bailing the Matildas out over and over.

But then Australia scored. 

From a Steph Catley corner, Alanna Kennedy launched herself like a Jeff Bezos vanity project into the stratosphere and banged a header into the corner.

One-nil to Australia and suddenly England were hanging on until half-time, with the Matildas buzzing.