As Caitlin Foord celebrated scoring the opening goal in Sydney, the fan park in Melbourne was lit up by a red flare.

It showed how optimistic the country is feeling about Australia's chances of going all the way in their home tournament - and how ready they are to celebrate.

After a stuttering start, Tony Gustavsson's side are starting to motor and the dream of winning the World Cup could become reality.

Some fans are starting to believe, albeit cautiously.

Oliver is a veteran of the Melbourne fan zone - he was here at 3am watching the men's team reach the last 16 at Qatar 2022.

"It's been absolutely incredible to see the growth of Australian football," he told BBC Sport.

"Last year we were here with maybe 60 of us in the fan zone [for the first game of Qatar 2022], and by the end it was full two hours before kick-off, 8,000 people.

"Now to have the World Cup, with all these people of different nationalities, to go to the games and then to the fan zone after, it's just amazing."

It was just as remarkable this time at Federation Square, where despite it being a chilly Monday midwinter night, there was barely standing room available - a sure sign of how popular the Matildas currently are in Australia.

The demographic mix was notable, with families on fold-out garden chairs - the sort of audience women's football usually courts and has been more associated with - rubbing shoulders with young lads singing chants, the sort of supporters more often thought of in relation with the men's game.

But it made for a healthy blend with a friendly and lively atmosphere - helped by Australia's comfortable victory over a disappointing Denmark.

'The weird Aussie confidence has got me'

Sam Kerr was immediately given the Australia captain's armband as she came on against Denmark

The only edge came when watching the final stages of the earlier kick-off between England and Nigeria, with several fans loudly claiming they are backing "anyone but England" at this World Cup.

Nevertheless, Chloe Kelly's winning penalty was greeted with begrudging applause - before the main event began, and ran according to plan.

Asked if Australia can now go all the way, Oliver said: "I'd like to think that. Every game from here on out is the final. We saw last night [Sweden v USA] anyone can win it."

It is a similar cautious confidence shared by friends Bella and Zac from Melbourne, who turned out in their big coats and green and gold regalia to cheer on the team.

While Bella has just got into supporting the Matildas at the World Cup, Zac has been a fan for "as long as he can remember".

"I've loved it, it has been a great experience having football on at a reasonable time," he said. "I am so used to waking up at 2am to watch football [in European leagues].

"All the way I'm not as confident about, although I thought we would demolish Denmark - it's the weird Aussie confidence you sometimes get, it's broached me today."

Bella added: "I think there are so many people like me who have been brought to soccer by the Women's World Cup, I think it has been a great initiation. I didn't buy tickets earlier because I didn't know it was going on. But it has been so, so good, I will definitely follow women's soccer more."

If confidence was being raised by the Matildas' performances, it will be skyrocketing now after the return to action of captain, driving force and all-time top scorer Sam Kerr.

The biggest cheer of the night was not reserved for Foord's opener or Hayley Raso making it 2-0, or even the final whistle confirming a quarter-final against France or Morocco in Brisbane.

It came when Gustavsson brought on Kerr with just over 10 minutes remaining for her first minutes of the tournament, having picked up a calf injury in training before their opening game against the Republic of Ireland.

'Kerr coming back is scary'

Sam Kerr briefly looked uncomfortable after losing her footing in the latter stages against Denmark

There were oohs and ahhs as Kerr shone in the closing moments, driving down the right and thundering a shot over the bar.

There were groans when she slipped on the Stadium Australia turf and briefly pulled a face of pain, before being able to continue. Gustavsson said he "got very nervous" as he saw Kerr crumple to the ground, and explained he "hopes she's OK".

So does the rest of the country. Kerr has a profile in Australia which surpasses just being a footballer. She is the poster girl of this World Cup; now the star is finally on stage.

"First of all Australia winning without Sam Kerr is impressive. Now she's coming back - it's scary!" former England international Sue Smith said on BBC One. "Great for Australia though."

Gustavsson, for his part, is refusing to get carried away.

"If a team wants to be successful, you can't rely on one player," he said after the game. "And that's no disrespect to Sam as she knows I think she's the best player in the world.

"Sam, coming back, doesn't have everything on her shoulders now. It's a team effort.

"Players are challenging me now, I've got more than 11 players good enough to start and multiple options to score goals."

With a team finding form and an icon back in action, the Australia fans could have much more to celebrate at this World Cup.

Flares at the ready, folks.