Eduan RoosColombo - If the cricket world considers New Zealand’s quarter-final win over South Africa a surprise, they haven’t seen anything yet, says Daniel Vettori.But according to the Kiwi captain, his side will need to produce an even better performance if they want to beat Sri Lanka in their World Cup semi-final on Tuesday.Vettori and his men beat the Proteas by 49 runs against all expectations in Mirpur on Friday. The victory followed one of the most dramatic batting collapses in World Cup history by South Africa.Vettori warned his team on Monday that they needed to forget about the win.“We have to move on very quickly because we now have much bigger things to think about. Of course we are very proud of beating South Africa, but we are only two victories away from being crowned world champions.”As was the case against South Africa, the Black Caps are not being given much of a chance against Sri Lanka. They have previously stumbled at the semi-final stage on five occasions and Sri Lanka beat them by 112 runs less than two weeks ago.“Everybody is talking about our semi-final record, but it’s a huge achievement for a small country to progress that far,” said Vettori.“It also does not matter what other people say because we are only focused on our goals.”However, he admitted that New Zealand would have to produce their best performance of the tournament to beat Kumar Sangakkara’s team at the Premadasa Stadium.“Up until now we have not been very consistent because in the group phase we played poorly virtually every time after winning a game. We have to be at our very best against Sri Lanka, who are very tough opponents in their back yard,” said Vettori.“We have had to rely on one or two guys to win games for us up until now. It was Jesse Ryder and Jacob Oram against South Africa and hopefully more guys can do their bit this time.”Vettori also hit out at the organisers’ decision to use the same batting strip as the one on which the home side beat England in their quarter-final at the weekend.“I thought that a new batting strip would only be fair, but clearly that’s not the case. The fact that this one was recently used means that Sri Lanka knows how to play on it and that it will favour their spinners.”Sangakkara said on Monday that Sri Lanka’s feet are firmly on the ground following their 10-wicket win over England at the weekend.“New Zealand showed against South Africa that they are capable of beating anybody. Terms such as psychological advantage and favourites mean absolutely nothing,” said Sangakkara.“We have played some excellent cricket, but your campaign will be remembered for what you do in the knockout games.”He said that Sri Lanka is holding thumbs that spinner Muttiah Muralitharan recovers in time from a hamstring injury.“Everybody is doing their best to ensure that he can play, but we have enough players capable of stepping into his shoes if necessary.”Sri Lanka won the World Cup in 1996 and has reached the semifinals on three occasions.