Who will be the winner in the Semifinal match between Australia and South Africa today?

I like SA to win with full heart, but I think Australia is going to win. If SA wins the toss, it should bat first. Only problem SA has is that it does not have a good spin bowler so it will be difficult for it to defend its total. But if SA allows Australia to bat first, I think SA will have very thin chance of winning. So the biggest mistake of SA is coming to world cup without a spinner. So it may lose the chance of winning world cup by this mistake alone. What do you think?