Olympic champion Jason Kenny suffered a quarter-final defeat in the men's sprint as his Track Cycling World Championships came to a premature end on day four in Minsk.
Kenny, who won the men's keirin on day three, was untroubled in advancing to the last eight, but lost his quarter-final with Sam Webster of New Zealand 2-0.
The 24-year-old from Bolton was seeking to add the world title after claiming his first on the bike on Friday.
His 2011 sprint win was awarded retrospectively after Gregory Bauge was stripped of the gold medal for an anti-doping infringement.
Frenchman Bauge, world champion in three of the last four years, was absent at the Minsk Arena, but the depth of the field was still strong.
