Ireland's Martyn Irvine won a silver medal in the scratch race at the World Track Championships in Colombia. Irvine put up a superb defence of the title he won last year but had to settle for second place after an exciting sprint finish with Ivan Kovalev of Russia. Meanwhile, Ryan Mullen came fourth in the men's four-kilometres individual pursuit. The 19-year-old finished in a time of 4 minutes 24.626 seconds but he was pipped by Marc Ryan of New Zealand who claimed third in 4 minutes 22.895secs. Caroline Ryan and Irvine are back in action today, racing in the individual pursuit and points race respectively.