In a 50 over one day cricket match if you get over 250 that is often a winnable position. Over 300 and you tend to be damn confident as that is a run rate greater than 100%.
So Australia sets a new world record and smashes 434 in 50 overs with Ponting 164 off 105 balls. Only dropped four wickets in beating the former world record for ODI batting of 398-5 and that was vs Kenya! Incidentally NZ had been 2nd with 397-5 vs Zimbabwe.
But South Africa achieved the impossible. They scored 438-9 (Gibbs getting 175 runs off 111 balls) and they did it on the second to last ball with no wickets in hand. It does not get much closer. Luckily the Aussies are no longer allowed to bowl under-arm in these situations.
Cric Info is calling it the greatest match of all. Hard to disagree.