BRISBANE (AFP) - The "lucky" ball boy who helped China save a penalty which sparked their run to the Asian Cup football quarter-finals has backed Alain Perrin's men to upset his beloved Australia on Thursday.

Twelve-year-old Stephan White became a sensation in China after telling goalkeeper Wang Dalei which way to dive when he saved a vital spot kick against Saudi Arabia.

Now, in a sign which will be welcomed by Chinese fans, the Brisbane schoolboy says a gut feeling tells him the visitors will prevail in the crunch clash in his home town.

"My heart says Australia to win, but my gut says China," Stephan told Brisbane's Courier-Mail newspaper. "I'll definitely be cheering for both goalkeepers."

His proclamation will be seen as portentous by superstitious Chinese fans, who also took it as a good omen when the Saudis left two balls behind after a training session.

"It means China will defeat Saudi Arabia 2-0 on Saturday," posted one Internet user. In the event, China won 1-0 after Stephan helped Wang stop Naif Hazazi's penalty.

He has been spared making another high-stakes penalty decision, however, as he won't be stationed behind the goal posts - much to the relief of his mother Suzie.

"There'd just be too much pressure on him if a penalty was awarded," she said. "Everybody would expect him to pick the right away again."

But in some ways Stephan cannot lose on Thursday as he would be happy for either team to win. "Whoever wins, I'll be supporting them for the rest of the tournament," he said.