A call to arms by injured superstar Sam Kerr provided the inspiration for Australia's 4-0 drubbing of Canada, with coach Tony Gustavsson saying his team was determined to do her proud.

The Chelsea striker and Matildas captain has yet to kick a ball at the Women's World Cup as she struggles with a calf injury sustained before their opening game.

But her animated presence on the bench helped the team in their statement do-or-die win over the Olympic champions which powered them into the last 16 -- a resounding answer to the critics after being upset 3-2 by Nigeria.

Kerr had declared herself available if needed, but Australia's all-time leading goal-scorer ultimately wasn't risked as her teammates rose to the occasion and gave her extra time to recover.

A relieved Gustavsson, who was facing the exit door if they had lost, said that Kerr's pre-match pep talk had been vital.

"Part of the reason why I think they were so united and performed the way they did was what Sam said to the team: 'Make sure you win without me so I can get another week to train and recover and get healthy'," he said.

"And the team responded and said: 'Yes we will. You sit on the bench tonight, and we'll win for you'.

"You could see that conviction and commitment from the players so that Sam gets another week of training."

Kerr made her Australia debut aged just 15. Now at her fourth World Cup, she has become one of the best players in women's football, with her profile soaring to new heights since moving to Chelsea in 2020.

She said on the eve of the game that despite the disappointment of not being on the field, she planned to do everything she could to motivate her teammates.

"I'm not the first person to get injured and I won't be the last. It's just something I've had to deal with, and I think I've dealt with it pretty well," she told FIFA.com.

"You have to be there for the team. This is a team sport, not an individual sport.

"It's actually been nice in a way to be on the other side and cheer on my teammates," she added. 

"I thought it was quite an eye-opener, and I've loved watching the girls. I'm really proud to be a part of this team."

The victory gave Kerr another full week to prove her fitness for next Monday's round of 16 clash in Sydney -– most likely against Denmark or China -- and Gustavsson a selection headache, with Mary Fowler expected to make way.

Gustavsson said he had a good feeling that the result would go their way.

"Sometimes you can just feel when things are going to go right," he said.

"The fact it is must-win all the way through (the rest of the World Cup) helps this team, because the pressure will be on every single game."