Chinese swimming coach Yao Zhengjie Friday warned the hosts are not guaranteed to clinch a gold medal at the Shanghai world championships despite mounting expectations of home success. China finished third in swimming events at the 2009 world championships in Rome, behind only the United States and Germany, and underlined their growing strength with a dominant showing at last year\'s Asian Games. \"The Shanghai worlds is the biggest competition before the 2012 London Games, so it is a good chance to get the swimmers ready,\" said Yao. \"I hope we can find some young talent in the women\'s relay at the Shanghai worlds,\" he added. \"Although we won the women\'s 4x200m freestyle relay and 4x100m medley relay at the last world championships in Rome 2009, we cannot guarantee a gold in Shanghai, as Australia and Canada both have claimed better results this year.\" China\'s 52-strong swimming team includes Olympics 200 metres butterfly gold medallist Liu Zige and rising star Sun Yang, who just missed out on breaking Grant Hackett\'s long-standing mark in the 1,500m freestyle at the Asian Games. Li Hua, secretary general of the China Swimming Association, said on Thursday that the world championships was a key event in the build-up to the Olympics and China still had ground to make up on other nations. \"Despite some progress in swimming in the past two years, China is still far behind some leading European countries and the US in this major event,\" he said. \"We will strive for good performances in such events as men\'s freestyle, women\'s butterfly, women\'s backstroke and relay.\" The FINA championships, which also include diving, synchronised swimming and water polo, start on Saturday with the swimming competition opening on July 24.