Mackenzie Arnold has become one of Australia's favourite sportspeople since her heroics at the weekend but she knows her fame will be fleeting if she is not at the top of her game in Wednesday's Women's World Cup semifinal against England.

Arnold was Player of the Match in Australia's quarterfinal against France on Saturday, making a string of saves late in the game and stopping three penalties in a shootout victory that captured the hearts of the host nation.

"I guess the last couple of days have been a pretty big whirlwind for me," she told reporters on Tuesday.

"Obviously I have not received attention like that (before), but at the same time I just tend to block it out because I know if I play like shit tomorrow it could be a whole different attention on me."

Arnold also took a penalty in the shootout, pinging Australia's fifth attempt against the post when successfully converting it would have sent them into the semifinals without the need for sudden death.

Coach Tony Gustavsson said he had selected Arnold for the role because of her technical ability from the spot and her mental strength, which she amply illustrated by bouncing back from the miss to win the day.

Arnold, who has only recently taken over as first-choice keeper for the Matildas, said she would step up and take another spot-kick on Wednesday if called upon.

"I am ready if I have to take one tomorrow, hopefully I don't," the 29-year-old added.

"But, yeah, the penalty order was called upon with me in the fifth in the line, and I wanted to try and do my job for the team.

"Unfortunately, in that specific incident I didn't, but I always want to do my job for the team. So if has to happen again, yes I will be ready."