Christchurch: Defending champions and strong contenders Australia once again underlined their superiority with a crushing nine-wicket victory over probable semi-finalist South Africa in a league match of the Women's World Cup 2000 match at the BIL Oval on Wednesday.One down batsman and vice-captain Karen Rolton overwhelmed the South African bowling with his rollicking century as Australia romped home with plenty of overs to spare. Chasing a modest target of 170 runs for victory, Australia reached 171 in 25 overs for loss of only opener Cherie Bambury's wicket.Karen smashed an unbeaten 107 runs from just 67 balls with 17 hits to the fence, while the other opener and captain Belinda Clark remained unbeaten on 49 runs off 71 balls with seven fours. The big victory put Australia as the favourites to retain their title as they have been scoring one big victory after another.Earlier, South Africa captain Kim Price won the toss and elected to bat. South Africa were well served by two useful partnerships for the second and fourth wickets as they scored 169 for eight in 50 overs.Linda Olivier and Daleen Terblanche added 35 runs for the second wicket after the early dismissal of Hanri Strydom. Linda scored 34 runs from 74 balls with six boundaries. Vice-captain Cindy Eksteen (46 runs, 59 balls, five fours) and Anina Burger (44 runs, 73 balls, five fours) then added 74 runs for the fourth wicket.