Competing against a field of 88 players - mostly boys from private schools - grade 5 pupil Mae won the gold medal, while classmate Rebecca snared silver. Both had perfect scores.

Amber, also in grade 5, won a distinction for finishing 10th. Their male teammates were Ege and Nick.

Mae and Rebecca won five more points between them than runner-up Woodleigh School.

Chess Kids is an Australian company that provides schools with chess products and sponsors interschool chess competitions.

CEO David Cordover said he could not recall two girls from one school ever getting perfect scores in a mixed tournament or finishing both first and second.

"Only 17per cent of junior chess players are girls and only one in 400 gets a perfect score, so this is an exceptional result for Patterson Lakes," he said.

Mae, Rebecca, Amber and teammates Sara, Paige and Meghan call themselves the Cyber Girls.

When they formed as a team at the start of the year, most did not believe they would be successful.

Their doubts were unfounded. In serious matches with the boys from various grades, the girls won all of them.

Mae (captain) and Rebecca were instrumental in leading their house to the school championship when they defeated a team of boys to win the shield.

The girls are also leading the school's individual championship.

"The boys at our school are used to getting beaten by Mae and Rebecca," said the school's volunteer chess coach Christian Bennett.

"But boys from other schools get a shock at how well the girls play, and many of them don't like it.

"Sometimes they even try to fudge the rules of chess and try to bluff them with their knowledge of the rules, but the girls are always firm but polite. They win the umpire's rulings and the games."

Mae, who joined the school last year because it had a chess team, has amazed everyone with her talent and application.