5 August 2012 Last updated at 22:21

Usain Bolt 'extremely happy' to retain 100m title

Jamaican Usain Bolt admits he did not have the best of starts in the 100m final, but is delighted to come through to clinch Olympic gold.

Bolt praises his training partner and compatriot Yohan Blake, who finished second, and says the silver medallist will be better at the next Olympics at Rio 2016.

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