The Matildas are waltzing into the knockout rounds at the Women's World Cup after eviscerating Canada 4-0 in Melbourne -- here's how the internet reacted.

What sweet sickness it is to dance along the knife edge.

World Cups are meant to have high stakes; the come from behind, the shock fall from grace, the lurch away from the void, and the lunge for immortality, none of it is supposed to feel good in the moment, it's not a leisure cruise, it's a cruel crucible.

Still, the torturous feeling Matildas fans were feeling ahead of arguably the team's most important ever game was as hard to describe as it was to stomach, excitement or nausea, or a mixture of both, or of neither.

Luckily, teetering between glory and doom is where football fans in this country feel most begrudgingly at home.

Sam Kerr, available for this match, started on the bench, as was probably expected. Mary Fowler, returned to the team after a concussion spell, and came in for Courtnee Vine.

Kerr, however, did not warm up with the rest of the team before the match, a detail which wasn't immediately zeroed in on by the faithful with neurotic precision.

The match kicked off.

Fowler was positioned as a central striker, with Caitlin Foord to her left, Hayley Raso to her right, and Emily van Egmond hovering behind. 

The opening minutes were as taut as a drum, each team streaking into the other's defensive third, conjuring the whiff of a chance, but nothing to really sate the appetite.

Then the drum skin tore: a flowing move down the left and Raso had the ball in the net, the stadium erupted.

But the play was called back for an offside earlier in the build up, on the left flank. A horrible bait and switch.

But then VAR reviewed it, and no, there was no offside to be found, a goal after all. A disjointed sense of joy, but overwhelming joy nonetheless. Raso fell to her knees when the verdict was reached.

The Matildas had their teal tails up, Raso forcing a super save low down to Canada keeper's left minutes later.

These moves had swept beautifully from one side to the other, no Kerr focal point was no problem as the forward three of hybrid attackers mixed and meshed beautifully.

Canada weren't cowed though and upped their tempo, forcing the Matildas to scramble and match it.

Slowly, though, Canada worked their way into things, keeping the ball, making steady progress up the pitch winning a corner or two, bearing down on Australia.

But it was all a cunning Australian ploy: a surge down the right, after a Canada turnover and Carpenter was unleashed, then van Egmond was released, then the ball was spinning wild and free in the box waiting for a finish, players crashing in with tackles and blocked shots.

It was Mary Fowler, poised and perfectly timed who arrived to crash the ball into the roof of the net. A counter attack the Matildas had executed perfectly.

And then VAR turned from hero to heel, and intervened again, this time crushing Australian hopes.

Ellie Carpenter was judged offside when Fowler had shot, and had been deemed involved enough in the play for the infringement to count. Marginal calls, both for and against the home team had made their mark on the game.

Then a minute later, in an act of cosmic hometown justice, the 2-0 lead was restored, as a corner was scuffed about by the Canada defence, before Raso swivelled and rolled it home. The outburst of defiant joy was palpable.

As Canada shrivelled slightly in attack, the seven minutes of first half added time were seen out assuredly, a welcome sight for Aussie fans after the Nigeria game.

Canada made four substitutions at half time, as clear an admission as there is that things hadn't gone to plan in the first half.

But it was the Aussies that started the second half the better, flashing a cross through the corridor of uncertainty, Kyra Cooney-Cross sending in a long range howitzer that needed tipping over, all good indicators the team was not going to meekly defend what they had and were pushing for more.

And more they got, as Caitlin Foord was set free by a lofted ball down the left. She speared in, taking her defender all the way to the by-line, then squared it for Fowler to scuff home, off the post, the least convincing of finishes, but enough.

3-0, and the Tillies were thrumming along, cruising to victory without Sam Kerr, and seemingly the pressure of the nation.

This was easy, breezy football, and Canada were flummoxed.

At the hour mark, Canada had yet to register a shot on target, to Australia's five. They'd made a couple of hundred more passes. Like Japan had earlier in the night to Spain, the Matildas were repeatedly bayoneting Canada on the counter.

Speaking of which, Arnold was called into action for the first time to repel a Canada counter attack, saving well with her feet.

Raso came off to a hero's ovation after two goals, Courtnee Vine came on. 20 minutes remained.

Fowler struck the base of the post after dancing into the box from the right. The Matildas were ravenous for more goals.

Clare Hunt was a brick wall, stuffing multiple forward runs, even after having suffered a nasty head clash. 

The sight of Sam Kerr removing the tape from her injured calf to put it up for the night was emblematic of just how smoothly the Matildas had gone about their business.

Canada bashed a shot that Arnold tipped athletically around the post, which would have been a nice consolation to have eased their pain.

Instead, a few moments later, the VAR instructed the referee to stop a Canadian counter and inspect the monitor; Gorry had had her foot trodden on, barely inside the area. Penalty to Australia.

Steph Catley's to take.

Steph Catley's to score. And the cake was iced.

The roar when the final whistle sounded was enough to boil the Yarra.

This was the kind of performance runs to the World Cup final are built on, the kind of win that inflates the spirit in a way that can't punctured and let down, that stokes the fires of ambition, that fans the flames of confidence, that puts an irresistible wind at your back. 

And it came when the Matildas needed it most.

On the knife edge in Melbourne, doom beckoned. Glory was seized.