LONDON, Aug 9 (Reuters) - United States won the latestbattles in their fierce track rivalry with Jamaica on Wednesdaywhile Usain Bolt cruised through to the 200 metres final wherehe will aim to prove once and for all he is an Olympic "legend". Bolt goes into Thursday's final seeking to become the firstman to win the 100 and 200 at two successive Olympics. The Jamaican and the training partner he playfully nicknamesThe Beast, compatriot Yohan Blake, comfortably won their 200semi-finals with both easing up towards the line. ... More...