(Reuters) -- Australia must beat South Africa in their forthcoming three-match series to stay on top of the world standings after tying with New Zealand. The series between the trans-Tasman rivals ended in a tie after the third test in Perth was drawn. The first two tests were also drawn. Australia's average dropped from 1.62 points to 1.50, giving South Africa the chance to overtake them in the official world rankings launched in May this year.
